fix Add hover info for language keywords #4340

[asukaminato0721]

Summary

Fixes #4340

see this from r-a, so impl it here.

Added documentation and Python language-reference links for language keywords.
Preserved existing type-aware hover information for operators such as in, not, is, and, and or.
Distinguished keywords with multiple grammatical roles:

• Iteration in shows iteration-specific documentation and the inferred iterable type.
• Membership in / not in shows membership-test documentation and __contains__ information.
• Compound forms such as is not, yield from, and raise ... from show their specific documentation.
• Context-sensitive keywords including from, if, else, for, as, and async select documentation based on their enclosing AST node.

Added support for the Python 3.15 lazy soft keyword, while avoiding hover results when lazy is used as an identifier or module name.

Test Plan

Added regression tests for keyword roles, compound operators, iteration versus membership, soft keywords, and lazy imports.

[meta-codesync]

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[codspeed-hq]

Unable to generate the flame graphs

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[github-actions]

According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅