gh-97607: a blank line after .. impl-detail:: in the Docs

[StevenHsuYL]

Add a blank line after .. impl-detail:: in the documentation for translation work.

If a blank line were missing, Sphinx would not build the paragraph after .. impl-detail:: during HTML file generation.

• Issue: Lack of a blank line after .. impl-detail:: #97607

[CAM-Gerlach]

Actually, the real problem here isn't with the source syntax, but rather than the custom impl-detail directive not handling it correctly (like the built in Sphinx directives do, e.g. admonition).

I've gone ahead and implemented a fix for that in #97652 , which should ensure translations work correctly for all three cases (0, 1 or 2 line breaks before directive content) anywhere the directive is used, now and in the future, makes the behavior consistent with the builtin directives, and substantially simplifies the directive code and logic, while not modifying either the source or the non-translated HTML output.

Therefore, with the fix to the underlying bug, the source changes in this PR won't be actually be necessary (and I've set that one to close this one, if/when successfully merged).

[StevenHsuYL]

The issue will be handled in #97652.
Close this PR.