unittest.mock docs: fix use of default role

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minor grammar fixes (from docs@python.org)

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#22613: fix several factual errors in builtin docs (thanks Jacques Ducasse)

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#22613: explain what "buffer" is in the struct documentation (thanks Jacques Ducasse)

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#22613: elaborate on arguments of shutil archival functions (thanks Jacques Ducasse)

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#22613: fix heading levels in tracemalloc docs (thanks Jacques Ducasse)

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#22613: document Cmd.cmdqueue (thanks Jacques Ducasse)

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#22613: minor other fixes in library docs (thanks Jacques Ducasse)

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#22613: remaining corrections in extending/reference docs (thanks Jacques Ducasse)

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Closes #22771: "verbose" is unused; deprecate it.

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Issue #17381: Fixed handling of case-insensitive ranges in regular expressions.

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Closes #22772: fix __ifloordiv__ and __itruediv__ docstring.

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extra : rebase_source : fc7cf1a688c47b2c570b379bbbd4d662303d7053