docs: date the __excluded__ and Raw directives to the release that shipped them (#1933)

[JarryShaw]

• Searched for similar pull requests

• Followed the coding style (make pylint, make mypy, make isort)

• make test passes, and a test case covers the change

• Added a changelog entry — N/A — centralised in docs(changelog): shared 1.5.0 changelog — long-lived, merges last (#610, #616, #617, #618, #620) #657

• docs — documentation only

Two versionchanged:: 1.3.3 directives describe changes that first shipped in 1.3.1.post8:

• Info.__iter__ gained its __excluded__ skip in ab8a21c7a.
• Raw became Raw(Protocol) with no packet field in a7d5df73c.

v1.3.1.post7 has neither change, and the files are unchanged from post8 through 1.3.3. Under the ruling on #1911, a post-release change is marked with its own post-release, so both directives now say 1.3.1.post8. The edits are docstring-only, and the AST is identical. docs/source/changelog/1.3.3.rst still lists both changes under 1.3.3; changelog edits stay with #657.

Closes #1933

[JarryShaw]

GOOD TO GO at 009f5b8df. A Sonnet cross-review scanned v1.3.1, every post-release to post28, and v1.3.3. In each tag up to post7, Info.__iter__ yields every key, and Raw(Data) takes packet both as a field and as a constructor argument. From post8 on, __iter__ skips __excluded__ and Raw(Protocol) has only protocol and error. Every post tag's name matches its __version__, and 1.3.1.post8 is on PyPI with wheels. Both files are AST-identical to main once docstrings are blanked. The 1.3.3 changelog page groups these changes under 1.3.3, which is a separate question for the historical changelog.