fix(markdown): handle newlines after indentation groups

[wanlingt]

Problem

Given

title 1
- item 1
- item 2

title 2

Title 2 will be rendered under the same indentation as item 2 as it did not break out of the <li> group.

title 1
- item 1
- item 2

  title 2

Replacing \n with an empty space prevents markdown from detecting \n\n that signifies a break from the list item.

The previous PR which tackled this issue #6917 was reverted as older versions of Safari could not handle Lookbehind in regular expressions

Solution

Replace   \n that comes after a list item with \n

Breaking Changes

• No - this PR is backwards compatible

Before & After Screenshots

BEFORE:

AFTER:

Tests

• In the form builder page, create a new Paragraph question
• For the Paragraph's content, insert the following (like the screenshot)

title 1
- item 1
- item 2
- item 3


title 2

• In the form builder, title 2 should not be indented
• In the public form page, title 2 should not be indented

[sebastianwzq]

Quite a smart approach actually! Wondering why we went with the lookbehind in the first place now. 😄
nit: the i in /gi indicates case-insensitive matching, we can actually remove them since newline characters dont have a case.

[wanlingt]

good catch! removed here bba36a8