formula: add/improve more API docs.

Closes #35266.
Fix warning
Overriding #initialize is not supported, so drop late validation
Unroll validation loop
Finally stop exposing url on Formula
Define install instead of making subclasses call standard_install
Remove unnecessary require from test
Decouple applying patches from staging the source
Allow debugging patching failures

Closes #33056.
Commit test updates that were supposed to be part of b76e26c9cf1fc805663d86b6d6d081f91f73ea18
Refactor patching tests
Remove unnecessary code from debugger
New formula: davmail

Closes #33416.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
gettext 0.19.4
gettext: update 0.19.4 bottle.
libqalculate: fix test
pdf2htmlex: update 0.12 bottle.
vavrdiasm 3.1 (new formula)

Closes #35026.
vavrdiasm: add 3.1 bottle.
pyqt: style nits