Cleanup: spelling in comments

Fix custom property editing with Python 3.10

Fix T92361: Zooming nodes clips text labels

While c7d94a7827a5be9343eea22a9638bb059f185206 exposed this bug,
this was caused by text widths being calculated without taking the zoom
level into account since drawing at a smaller size is often wider than
the width of the larger text scaled by the zoom.

Cleanup: clang-tidy, spelling

Fix T92293: Clipped labels for graph editor modifiers

While c7d94a7827a5be9343eea22a9638bb059f185206 exposed this bug,
this was caused by a discrepancy in padding where labels would
have additional padding when drawing without emboss.
The padding made widget drawing behave as if the text took up more
room causing it to be clipped.

Now labels are considered the same width with/without emboss.

Cleanup: cross-reference right pointing arrow literal

This value is defined in the UI module, but happens to be used
in string_search.cc too. Note that these references need to be kept in
sync. Use escaped utf-8 sequence since the literal can be avoided.

Also replace BLI_str_utf8_as_unicode calls with constant assignments
as these values are known there is no need to decode a utf-8 sequence.

Cleanup: line length in Python scripts

Cleanup: spelling in comments

Cleanup: spelling in comments, use C style comments

Fix crash when creating a new window fails

Also add operator error report.