[passlib] Small changes

[srittau]

• Add a few Self return annotations.
• Add a few # type: ignore[override].
• Add a few @deprecated annotations.

Should help with #14194

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

archinstall (https://github.com/archlinux/archinstall)
+ ./archinstall/tui/curses_menu.py:710: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
+ https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
+ Please report a bug at https://github.com/python/mypy/issues
+ version: 1.15.0
+ ./archinstall/tui/curses_menu.py:710: : note: use --pdb to drop into pdb
+ Traceback (most recent call last):
+   File "mypy/checkexpr.py", line 5903, in accept
+   File "mypy/nodes.py", line 1889, in accept
+   File "mypy/checkexpr.py", line 3284, in visit_member_expr
+   File "mypy/checkexpr.py", line 3309, in analyze_ordinary_member_access
+   File "mypy/checkmember.py", line 207, in analyze_member_access
+   File "mypy/checkmember.py", line 226, in _analyze_member_access
+   File "mypy/checkmember.py", line 344, in analyze_instance_member_access
+   File "mypy/meet.py", line 96, in meet_types
+   File "mypy/subtypes.py", line 223, in is_proper_subtype
+   File "mypy/subtypes.py", line 351, in _is_subtype
+   File "mypy/types.py", line 1469, in accept
+   File "mypy/subtypes.py", line 581, in visit_instance
+   File "mypy/subtypes.py", line 2095, in infer_class_variances
+   File "mypy/subtypes.py", line 2057, in infer_variance
+   File "mypy/subtypes.py", line 186, in is_subtype
+   File "mypy/subtypes.py", line 351, in _is_subtype
+   File "mypy/types.py", line 3033, in accept
+   File "mypy/subtypes.py", line 1079, in visit_partial_type
+ RuntimeError: Partial type "<partial list[?]>" cannot be checked with "issubtype()"