Fix linters and some errors

[kaz-on]

Hi.
This PR will fix following.

• package.json
  • Fix description of xvlog arguments setting.
• XvlogLinter.ts
  • Fix xvlog arguments setting requiring additional whitespace.
  • Fix error message not being detected correctly if it contains brackets [].
  • Add support for warning messages.
• VerilatorLinter.ts
  • Fix file paths being treated as regular expressions.
• LintManager.ts
  • Add linting for open documents on launch.
• extension.ts
  • Fix Verilog: Rerun lint tool command not working.
• ctags.ts, DefinitionProvider.ts, HoverProvider.ts
  • Fix errors reported in the Developer Tools that the variable is undefined.

[kaz-on]

I have made an additional fix for some cases where ctags symbols were not updated.
I will open the PR after merging of this PR, because the fix has a dependency with this PR.
Or is it better to modify this PR itself?

[mshr-h]

LGTM. Thanks! 😄

I will open the PR after merging of this PR, because the fix has a dependency with this PR.
Sure.