- Added space below non doc-string comments to make it clear
these aren't comments for the symbols directly below them.
- Use doxy sections for some headers.
- Minor improvements to doc-strings.
Ref T92709
Somehow, the file from T71329 has an empty curve profile. While that may
be a problem in itself, it's reasonable to avoid asserts or crashes when
loading or drawing such a CurveProfile. This commit just makes sure the
table always has a single vertex, and adds some checks in drawing code.
