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-rust.json

@@ -1,9 +1,9 @@
 {
   "url": "https://github.com/tree-sitter/tree-sitter-rust",
-  "rev": "ab7f7962073fec96e0b64fbd1697263fe2c79281",
-  "date": "2021-02-16T21:17:08-08:00",
-  "path": "/nix/store/zy2sccixlk8lwkqamikz03j42s13ndjp-tree-sitter-rust",
-  "sha256": "06zmbwgsvyaz0wgja8r3ir06z67gix7i62zj0k3bbng6smdnhp9w",
+  "rev": "20f064bd758f94b8f47ce5a21e4383c7349ca182",
+  "date": "2021-03-04T14:06:14-08:00",
+  "path": "/nix/store/za0yxqjjp9vxgwrp014qwv2v2qffl0di-tree-sitter-rust",
+  "sha256": "118vkhv7n3sw8y9pi0987cgdcd74sjqwviijw01mhnk3bkyczi3l",
   "fetchSubmodules": false,
   "deepClone": false,
   "leaveDotGit": false