gh-95913: Copyedit & xref FrameInfo in Whatsnew inspect section

[CAM-Gerlach]

Part of #95913

This applies the standard copyediting and formatting to the inspect section in the Python 3.11 What's New, as well as explicitly mentions/references the new inspect.FrameInfo objects. Specifically:

• Explicitly name and link the new FrameInfo/Traceback class instances returned by various inspect functions and what it replaces (a namedtuple-like object)
• Break prose list of functions into bulleted list for readability
• Don't show redundant module name in inspect module APIs
• Other small Sphinx/textual tweaks

Also, it makes a couple directly related fixes in the inspect module library documentation:

• Add missing "Changed in 3.11" annotation to inspect.Traceback
• Fix indent and wording of that under inspect.FrameInfo
• Add missing "New in 3.11" annotation to inspect.ismethodwrapper mentioned in What's New, and fix broken cross-references within due to bad Sphinx syntax

• Issue: gh-95913