tree-sitter: 1.18.2 -> 0.19.3

Update the grammars and add `allGrammars` derivation.
`nix-build "<nixpkgs>" -A tree-sitter.allGrammars` will create a
derivation with symlinks to all the grammars

pkgs/development/tools/parsing/tree-sitter/grammars/tree-sitter-ocaml.json

@@ -1,9 +1,9 @@
 {
   "url": "https://github.com/tree-sitter/tree-sitter-ocaml",
-  "rev": "4ec9ee414dadc2b6e7325a9f8124d02f6cd8c250",
-  "date": "2020-09-18T02:13:40+02:00",
-  "path": "/nix/store/dszjdnwnbziqxav2khs85026msm6fasz-tree-sitter-ocaml",
-  "sha256": "0wy85940fhmrnz7c1gk6xkipm8ixzalq5q4i7mcc6wnjiiwq60gx",
+  "rev": "19a8d2aab425c4c4c8dc6a882e67c37010620c3b",
+  "date": "2021-03-08T16:57:09-08:00",
+  "path": "/nix/store/y8jsf6vp278svqm4c6xnl4i6vanslrkk-tree-sitter-ocaml",
+  "sha256": "0c5wjanka87bhha0aq3m5p448apxhv8hndlqvhly6qafj99jp85i",
   "fetchSubmodules": false,
   "deepClone": false,
   "leaveDotGit": false