Block on other signature help triggers

[DanielRosenwasser]

#24915 implemented trigger characters for signature help, but only blocked signature help inside of a string.

As @mhegazy mentioned in #24915 (comment), we still need to block character triggers:

• In parenthesized expressions
• In comments
• In JSX text
• On commas outside of argument lists

[mhegazy]

@DanielRosenwasser u promised to get this in shortly after #24915