Add HEAD support to formula + fix linting issues

[ansonhoyt]

Add head block to allow installing from main branch: brew install --HEAD tobi/try/try

The HEAD build includes lib/tui.rb and lib/fuzzy.rb which are required by the current codebase but not present in the v1.0.0 release.

Also fixes pre-existing brew audit issues:

❯ brew audit tobi/try/try
tobi/try/try
  * Stable: `version 1.0.0` is redundant with version scanned from URL
  * line 6, col 3: `version` (line 6) should be put before `sha256` (line 5)
  * line 37, col 4: Final newline missing.
Error: 3 problems in 1 formula detected.