refactor(linter/plugins): shorten code in tokens methods (#16073)

Pure refactor. Shorten code in token methods.

The diff is large, but it's purely:

1. Remove redundant `else` clauses where the `if` block always `return`s.
2. Use early `return` where possible to reduce `if` / `else` nesting.
3. Compress short `if (condition) { doStuff(); }` blocks to single line `if (condition) doStuff();`

No behavioral changes at all - simply syntactical transform. The last one in particular is personal stylistic preference really - I just find compressing short `if` statements to a single line makes the code easier to scan.

Author: overlookmotel