Numbered headings (for example starting with 1.) are not translated with Sphinx

[n-peugnet]

What version of myst-parser are you using?

v2.0.0-18-g330e96a

What version dependencies are you using?

$ pip list
Package                       Version    Editable project location
----------------------------- ---------- -----------------------------------
accessible-pygments           0.0.4
alabaster                     0.7.13
astroid                       3.0.2
asttokens                     2.4.1
Babel                         2.14.0
beautifulsoup4                4.12.2
cachetools                    5.3.2
certifi                       2023.11.17
cfgv                          3.4.0
chardet                       5.2.0
charset-normalizer            3.3.2
colorama                      0.4.6
coverage                      7.4.0
decorator                     5.1.1
distlib                       0.3.8
docutils                      0.19
exceptiongroup                1.2.0
executing                     2.0.1
filelock                      3.13.1
identify                      2.5.33
idna                          3.6
imagesize                     1.4.1
iniconfig                     2.0.0
ipython                       8.19.0
jedi                          0.19.1
Jinja2                        3.1.2
linkify-it-py                 2.0.2
markdown-it-py                3.0.0
MarkupSafe                    2.1.3
matplotlib-inline             0.1.6
mdit-py-plugins               0.4.0
mdurl                         0.1.2
myst-parser                   2.0.0      /home/nicolas/Documents/MyST-Parser
nodeenv                       1.8.0
packaging                     23.2
parso                         0.8.3
pexpect                       4.9.0
pip                           22.0.2
platformdirs                  4.1.0
pluggy                        1.3.0
pre-commit                    3.6.0
prompt-toolkit                3.0.43
ptyprocess                    0.7.0
pure-eval                     0.2.2
pydata-sphinx-theme           0.13.0rc4
Pygments                      2.17.2
pyproject-api                 1.6.1
pytest                        7.4.4
pytest-cov                    4.1.0
pytest-datadir                1.5.0
pytest_param_files            0.6.0
pytest-regressions            2.5.0
PyYAML                        6.0.1
requests                      2.31.0
ruamel.yaml                   0.18.5
ruamel.yaml.clib              0.2.8
setuptools                    59.6.0
six                           1.16.0
snowballstemmer               2.2.0
soupsieve                     2.5
Sphinx                        6.2.1
sphinx-autodoc2               0.5.0
sphinx-book-theme             1.0.0rc2
sphinx-copybutton             0.5.2
sphinx-design2                0.4.0
sphinx_pyscript               0.1.0
sphinx_pytest                 0.2.0
sphinx_tippy                  0.4.1
sphinx-togglebutton           0.3.2
sphinxcontrib-applehelp       1.0.7
sphinxcontrib-devhelp         1.0.5
sphinxcontrib-htmlhelp        2.0.4
sphinxcontrib-jsmath          1.0.1
sphinxcontrib-qthelp          1.0.6
sphinxcontrib-serializinghtml 1.1.9
sphinxext-opengraph           0.9.1
sphinxext-rediraffe           0.2.7
stack-data                    0.6.3
tomli                         2.0.1
tox                           4.11.4
traitlets                     5.14.0
typing_extensions             4.9.0
uc-micro-py                   1.0.2
urllib3                       2.1.0
virtualenv                    20.25.0
wcwidth                       0.2.12
wheel                         0.37.1

What operating system are you using?

Linux

Describe the Bug

When a heading is manually numbered: starts with a number followed by a dot then a space, it is not translated in the Sphinx output. While the following works as expected in rST:

python -m virtualenv .venv
. .venv/bin/activate
pip install sphinx==7.1.2
sphinx-quickstart --sep -p test -a test -v test -r test -l en
echo '1. Hello world
==============

' > source/index.rst
mkdir -p source/locales/fr/LC_MESSAGES
echo '#: ../../source/index.rst:1
msgid "1. Hello world"
msgstr "1. Bonjour monde"
' > source/locales/fr/LC_MESSAGES/index.po
make html O='-Dlanguage=fr -v'
sed -n '32,36p' build/html/index.html 

Which outputs:

            
  <section id="hello-world">
<h1>1. Bonjour monde<a class="headerlink" href="#hello-world" title="Lien permanent vers cette rubrique">¶</a></h1>
</section>

Expected Behavior

The headings should be translated.

To Reproduce

Here is a diff for the tests that shows this issue:

diff --git a/tests/test_sphinx/sourcedirs/gettext/fr/LC_MESSAGES/index.po b/tests/test_sphinx/sourcedirs/gettext/fr/LC_MESSAGES/index.po
index 43e5320..943eb23 100644
--- a/tests/test_sphinx/sourcedirs/gettext/fr/LC_MESSAGES/index.po
+++ b/tests/test_sphinx/sourcedirs/gettext/fr/LC_MESSAGES/index.po
@@ -125,3 +125,6 @@ msgid ".. image:: fun-fish.png\n"
 "   :alt: Fun Fish 3"
 msgstr ".. image:: poisson-amusant.png\n"
 "   :alt: Poisson amusant 3"
+
+msgid "1. numbered title"
+msgstr "1. titre numéroté"
diff --git a/tests/test_sphinx/sourcedirs/gettext/index.md b/tests/test_sphinx/sourcedirs/gettext/index.md
index a721944..05998e3 100644
--- a/tests/test_sphinx/sourcedirs/gettext/index.md
+++ b/tests/test_sphinx/sourcedirs/gettext/index.md
@@ -61,3 +61,5 @@ doctest block
 ```{figure} fun-fish.png
 :alt: Fun Fish 3
 ```
+
+## 1. numbered title
diff --git a/tests/test_sphinx/test_sphinx_builds/test_gettext.pot b/tests/test_sphinx/test_sphinx_builds/test_gettext.pot
index 933b8b6..4d8b7d2 100644
--- a/tests/test_sphinx/test_sphinx_builds/test_gettext.pot
+++ b/tests/test_sphinx/test_sphinx_builds/test_gettext.pot
@@ -79,3 +79,7 @@ msgstr ""
 #: ../../index.md:61
 msgid "Fun Fish 3"
 msgstr ""
+
+#: ../../index.md:65
+msgid "1. numbered title"
+msgstr ""
diff --git a/tests/test_sphinx/test_sphinx_builds/test_gettext_additional_targets.pot b/tests/test_sphinx/test_sphinx_builds/test_gettext_additional_targets.pot
index 11c51d4..7cb2f53 100644
--- a/tests/test_sphinx/test_sphinx_builds/test_gettext_additional_targets.pot
+++ b/tests/test_sphinx/test_sphinx_builds/test_gettext_additional_targets.pot
@@ -127,3 +127,7 @@ msgstr ""
 #: ../../index.md:61
 msgid "Fun Fish 3"
 msgstr ""
+
+#: ../../index.md:65
+msgid "1. numbered title"
+msgstr ""
diff --git a/tests/test_sphinx/test_sphinx_builds/test_gettext_html.html b/tests/test_sphinx/test_sphinx_builds/test_gettext_html.html
index 469e188..0db99d0 100644
--- a/tests/test_sphinx/test_sphinx_builds/test_gettext_html.html
+++ b/tests/test_sphinx/test_sphinx_builds/test_gettext_html.html
@@ -156,6 +156,14 @@
     <figure class="align-default">
      <img alt="Poisson amusant 3" src="_images/fun-fish.png"/>
     </figure>
+    <section id="numbered-title">
+     <h2>
+      1. titre numéroté
+      <a class="headerlink" href="#numbered-title" title="Lien permanent vers cette rubrique">
+       ¶
+      </a>
+     </h2>
+    </section>
    </section>
   </div>
  </div>
diff --git a/tests/test_sphinx/test_sphinx_builds/test_gettext_html.resolved.xml b/tests/test_sphinx/test_sphinx_builds/test_gettext_html.resolved.xml
index 231ca33..0eb02c1 100644
--- a/tests/test_sphinx/test_sphinx_builds/test_gettext_html.resolved.xml
+++ b/tests/test_sphinx/test_sphinx_builds/test_gettext_html.resolved.xml
@@ -91,3 +91,6 @@
         <image alt="Poisson amusant 2" candidates="{'*': 'fun-fish.png'}" uri="fun-fish.png">
         <figure>
             <image alt="Poisson amusant 3" candidates="{'*': 'fun-fish.png'}" uri="fun-fish.png">
+        <section ids="numbered-title" names="1.\ numbered\ title 1.\ titre\ numéroté">
+            <title>
+                1. titre numéroté
diff --git a/tests/test_sphinx/test_sphinx_builds/test_gettext_html.xml b/tests/test_sphinx/test_sphinx_builds/test_gettext_html.xml
index dfc5f41..aae502a 100644
--- a/tests/test_sphinx/test_sphinx_builds/test_gettext_html.xml
+++ b/tests/test_sphinx/test_sphinx_builds/test_gettext_html.xml
@@ -91,3 +91,6 @@
         <image alt="Poisson amusant 2" candidates="{'*': 'fun-fish.png'}" uri="fun-fish.png">
         <figure>
             <image alt="Poisson amusant 3" candidates="{'*': 'fun-fish.png'}" uri="fun-fish.png">
+        <section ids="numbered-title" names="1.\ numbered\ title 1.\ titre\ numéroté">
+            <title>
+                1. titre numéroté

And here is pytest's output with this patch applied:

E           AssertionError: FILES DIFFER:
E           /tmp/pytest-of-nicolas/pytest-44/test_gettext_html0/test_sphinx_builds/test_gettext_html.xml
E           /tmp/pytest-of-nicolas/pytest-44/test_gettext_html0/test_sphinx_builds/test_gettext_html.obtained.xml
E           HTML DIFF: /tmp/pytest-of-nicolas/pytest-44/test_gettext_html0/test_sphinx_builds/test_gettext_html.obtained.diff.html
E           --- 
E           +++ 
E           @@ -91,6 +91,6 @@
E                    <image alt="Poisson amusant 2" candidates="{'*': 'fun-fish.png'}" uri="fun-fish.png">
E                    <figure>
E                        <image alt="Poisson amusant 3" candidates="{'*': 'fun-fish.png'}" uri="fun-fish.png">
E           -        <section ids="numbered-title" names="1.\ numbered\ title 1.\ titre\ numéroté">
E           +        <section ids="numbered-title" names="1.\ numbered\ title">
E                        <title>
E           -                1. titre numéroté
E           +                1. numbered title

tests/test_sphinx/conftest.py:135: AssertionError

[n-peugnet]

After a debugging session, it seems to be again, somewhat related to sphinx-doc/sphinx#8852