Previously, we would guess that "Times New Roman Bold" is a regular
weight font because its name contains the substring "Roman", even though
the font correctly sets the BOLD flag (FT_STYLE_FLAG_BOLD). Invert the
logic to give priority to the flag, as its presence is clearly more
robust than a substring check.

s.find(w) >= 0 is just an obfuscated way to write w in s, so change
that.

Obviously font properties extraction could be improved in a lot of ways, but this should close #5574.

PR Summary

PR Checklist

• Has Pytest style unit tests
• Code is Flake 8 compliant
• New features are documented, with examples if plot related
• Documentation is sphinx and numpydoc compliant
• Added an entry to doc/users/next_whats_new/ if major new feature (follow instructions in README.rst there)
• Documented in doc/api/api_changes.rst if API changed in a backward-incompatible way