FIX: Restore D213 in flake8

This got accidentally ignored in matplotlib#25147.

We want D213 (matplotlib#17125, matplotlib#17193)
https://matplotlib.org/devdocs/devel/document.html#quote-positions

Author: timhoffm

.flake8

@@ -18,7 +18,9 @@ ignore =
     D301,
     D400, D401, D403, D404
     # ignored by pydocstyle numpy docstring convention
-    D107, D203, D212, D213, D402, D413, D415, D416, D417,
+    D107, D203, D212, D402, D413, D415, D416, D417,
+    # while D213 is ignored by the numpy docstring convention, it's left out above,
+    # because we want to enforce it.
 
 exclude =
     .git

lib/matplotlib/pyplot.py

@@ -1002,7 +1002,8 @@ def gcf() -> Figure:
 
 
 def fignum_exists(num: int | str) -> bool:
-    """Return whether the figure with the given id exists.
+    """
+    Return whether the figure with the given id exists.
 
     Parameters
     ----------

tools/gh_api.py

@@ -97,8 +97,7 @@ def post_gist(content, description='', filename='file', auth=False):
     return response_data['html_url']
 
 def get_pull_request(project, num, auth=False):
-    """get pull request info  by number
-    """
+    """Return the pull request info for a given PR number."""
     url = f"https://api.github.com/repos/{project}/pulls/{num}"
     if auth:
         header = make_auth_header()