fix(autofmt): remove extra whitespace before commas in for-loop tuple patterns

[costajohnt]

Summary

Fixes #5348

dx fmt was adding extra spaces before commas in for-loop tuple destructuring patterns:

// Before (incorrect)
for (index , name , value) in data.iter() {

// After (correct)
for (index, name, value) in data.iter() {

The root cause was that forloop.pat.clone().into_token_stream() uses proc_macro2::TokenStream::Display, which inserts a space between every token including before commas in tuple patterns.

The fix adds an unparse_pat helper that routes the pattern through prettyplease for proper formatting, following the existing unparse_expr pattern.

Test plan

• Added forloop_tuple.rsx sample test covering 3-element tuple, simple ident, 2-element tuple, and wildcard patterns
• All 69 dioxus-autofmt tests pass
• Existing ifchain_forloop test continues to pass (simple for i in b regression)

[jkelleyrtp]

Thanks!