Added watch option to re-run the linters when a file changes ⌚️

[01taylop]

Details

What have you changed?

• Added watch option to re-run the linters when a file either changes, is added, or deleted.

Why are you making these changes?

• Re-running the lint checks when a file changes is a useful feature to engineers. At the stage all files are re-linted when a file is changed. Though this could change;
  • Option 1: Re-lint only the file which changed, and ask the user if they would like to lint all files again after.
    • This would be beneficial to quickly fix a single file and then move onto the next.
  • Option 2: Set up different watchers for the different linters and only re-run the relevant one.
    • This one would provide for a faster feedback loop.
  • The concern with both options is that providing a green success message may be confusing as there may be lint errors in other files which have not been re-linted.
  • Option 3: Keep track of lint errors, update that when a single file is linted again, and display all of the results again.
    • This option requires more work and must not introduce confusing or misleading results.