runtime(help): Update help syntax

runtime(help): Update help syntax

This commit makaes the following changes to the vim help syntax:

- fix excessive URL detection in help, because `file:{filename}` in
  doc/options.txt is determined to be a URL.
- update highlighting N for :resize in help
- split Italian-specific syntax into separate help script
- highlight `Note` in parentheses in help
- update 'titlestring' behaviour in documentation for invalid '%' format

closes: #15883

Signed-off-by: Milly <milly.ca@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>