Add page for pure_eval integration (#1907)

Related:

getsentry/sentry-python#748
getsentry/sentry-python#762
getsentry/sentry-python#763

__tests__/__snapshots__/documentation.js.snap

@@ -377,6 +377,7 @@ Array [
   "platforms/python/index.html",
   "platforms/python/logging/index.html",
   "platforms/python/migration/index.html",
+  "platforms/python/pure_eval/index.html",
   "platforms/python/pyramid/index.html",
   "platforms/python/pyspark/index.html",
   "platforms/python/redis/index.html",

src/collections/_documentation/platforms/python/index.md

@@ -267,6 +267,7 @@ For more information, see:
 
 - [Logging](/platforms/python/logging/)
 - [GNU Backtrace](/platforms/python/gnu_backtrace/)
+- [pure_eval](/platforms/python/pure_eval/)
 - [Redis](/platforms/python/redis/)
 - [SQLAlchemy](/platforms/python/sqlalchemy/)
 

src/collections/_documentation/platforms/python/pure_eval.md

@@ -0,0 +1,23 @@
+---
+title: pure_eval
+sidebar_order: 9
+---
+
+{% version_added 0.16.2 %}
+
+This integration uses [`pure_eval`](https://github.com/alexmojaki/pure_eval) to safely evaluate additional expressions in the source code and display their values alongside other local variables.
+
+**This integration is experimental.** It may be removed in minor versions.
+
+Python version 3.5 or greater is required.
+
+To install dependencies, either `pip install 'sentry-sdk[pure_eval]'` or `pip install pure_eval executing asttokens`.
+
+Add ``PureEvalIntegration()`` to your ``integrations`` list:
+
+```python
+import sentry_sdk
+from sentry_sdk.integrations.pure_eval import PureEvalIntegration
+
+sentry_sdk.init("___PUBLIC_DSN___", integrations=[PureEvalIntegration()])
+```