fix(rules): remove no-unused-variable from the 'tslint:all' config

[DJMcNab]

fixes #4046

PR checklist

• Addresses an existing issue: no-unused-variable is deprecated. #4046
• New feature, bugfix, or enhancement
  • Includes tests

Overview of change:

Remove the no-unused-variable rule from the tslint:all config, as it was deprecated in #3919. Without this tslint gives a warning for projects extending tslint:all, which can be seen in #4046.

An alternative is to comment out the line "no-unused-variable": true with a note about its deprecation, as for no-invalid-this:

tslint/src/configs/all.ts

Line 117 in 0a676b7

// "no-invalid-this": Won't this be deprecated?

However, I think this is an oversight from #2417, as this comment says to remove the comment for a future deprecation.

EDIT: Additionally tslint:all doesn't include deprecated rules

CHANGELOG.md entry:

[bugfix] remove no-unused-variable from tslint:all

[giladgray]

please redo this with the minimal diff. do not apply your tslint config to this file.

[DJMcNab]

How should I do this - your repository uses husky and pretty-quick, which automatically runs prettier --write on any staged file precommit, then git adds the resulting file. This makes the changes that you do not want. Should I disable prettier for the file (by adding it to .prettierignore)?

I can then remove it from .prettierignore if you want.

EDIT: done. But should the prettier changes added in #4012 be actually run on each file at some point?

[giladgray]

@DJMcNab yes we'll do the prettier stuff in one go at some point.

[DJMcNab]

That's fine, thanks. For future reference in case anyone finds it useful - to make prettier ignore the file, I just:

• Added * to .prettierignore
• Staged the changes (except those to .prettierignore)
• Committed the changes
• Reset .prettierignore