Merge pull request #4034 from ilankri/ocaml

Complete `OCaml.gitignore`

OCaml.gitignore

@@ -8,7 +8,14 @@
 *.cmxs
 *.cmxa
 
-# ocamlbuild working directory
+# Files containing detailed information about the compilation (generated
+# by `ocamlc`/`ocamlopt` when invoked using the option `-bin-annot`).
+# These files are typically useful for code inspection tools
+# (e.g. Merlin).
+*.cmt
+*.cmti
+
+# ocamlbuild and Dune default working directory
 _build/
 
 # ocamlbuild targets