Cleanup: convert caml_format to .res.

Author: cristianoc

CHANGELOG.md

@@ -40,6 +40,7 @@
 - Convert OCaml codebase to snake case style. https://github.com/rescript-lang/rescript-compiler/pull/6702
 - Refactor uppercase exotic ident handling. https://github.com/rescript-lang/rescript-compiler/pull/6779
 - Fix `-nostdlib` internal compiler option. https://github.com/rescript-lang/rescript-compiler/pull/6824
+- Convert `caml_format` to `.res`. https://github.com/rescript-lang/rescript-compiler/pull/6834
 
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