`includeRegExpList` ignores capture groups

[twiddler]

Hey there and thanks for the great extension! 👋

I am using this extension with a few simple custom regular expressions in settings.json, e.g. for checking variable names when declaring them for the first time, and those work great and as expected. Today however, I encountered something unexpected when trying to match only the second argument of i18next's t(key, defaultValue) function if it is a string literal:

{
  "cSpell.includeRegExpList": [
    "\\bt\\(\\s*[^,]+\\s*,\\s*'([^']+)'"
  ]
}

Instead of just spellchecking what's inside the capture group ([^']*), the whole regex is used for spellchecking, so t(key, gets spellchecked, too. I expected cSpell to only spellcheck what is matched by a capture group, at least if one is present. As a workaround, I now use a lookbehind and a lookahead:

{
  "cSpell.includeRegExpList": [
    "(?<=\\bt\\(\\s*[^,]+\\s*,\\s*')[^']+(?=')"
  ]
}

I'd appreciate if you'd consider matching only capture groups if present. 🙏