[formatter] remove unnecessary parentheses in `return`

currently, deno formatter converts `(1)` to `1` which is good, but it doesn't convert `return (1)` to `return 1` which prettier does.

The issue does not name a source file, test, or entry point. Locate the formatter logic for parenthesized return expressions and inspect existing tests for `(1)` versus `return (1)`. Done means the formatter produces `return 1` while preserving required parentheses and the relevant tests pass.

Written by the indexing model from the issue text.