feat(fga): add FGA grammar

FGA is the DSL for [OpenFGA](https://openfga.dev/) authorization models
- a zanzibar-like Role-Based Access Control system.

SUPPORTED_LANGUAGES.md

@@ -80,6 +80,7 @@ ecma (queries only)[^ecma] | unstable | `HFIJL` |   | @steelsojka
 [facility](https://github.com/FacilityApi/tree-sitter-facility) | unstable | `HFIJ ` |   | @bryankenote
 [faust](https://github.com/khiner/tree-sitter-faust) | unstable | `H  J ` |   | @khiner
 [fennel](https://github.com/alexmozaidze/tree-sitter-fennel) | unstable | `HF JL` |   | @alexmozaidze
+[fga](https://github.com/matoous/tree-sitter-fga) | unstable | `H    ` |   | @matoous
 [fidl](https://github.com/google/tree-sitter-fidl) | unstable | `HF J ` |   | @chaopeng
 [firrtl](https://github.com/tree-sitter-grammars/tree-sitter-firrtl) | unstable | `HFIJL` |   | @amaanq
 [fish](https://github.com/ram02z/tree-sitter-fish) | unstable | `HFIJL` |   | @ram02z

lua/nvim-treesitter/parsers.lua

@@ -550,6 +550,14 @@ return {
     maintainers = { '@alexmozaidze' },
     tier = 2,
   },
+  fga = {
+    install_info = {
+      revision = '44bfe4e15dc11969f1a23e5f0fa9d8e961268721',
+      url = 'https://github.com/matoous/tree-sitter-fga',
+    },
+    maintainers = { '@matoous' },
+    tier = 2,
+  },
   fidl = {
     install_info = {
       revision = '0a8910f293268e27ff554357c229ba172b0eaed2',

runtime/queries/fga/highlights.scm

@@ -0,0 +1,50 @@
+(call_expression
+  function: (identifier) @function)
+
+(call_expression
+  function: (selector_expression
+    field: (identifier) @function.method))
+
+((type_identifier) @type.builtin
+  (#match? @type.builtin "^(string|int|map|uint|list|timestamp|bool|duration|double|ipaddress)$"))
+
+(condition_declaration
+  name: (identifier) @function)
+
+(version) @number
+
+[
+  "*"
+  "/"
+  "%"
+  ">>"
+  "<<"
+  "&"
+  "&^"
+] @operator
+
+[
+  "+"
+  "-"
+  "|"
+  "^"
+] @operator
+
+[
+  "or"
+  "and"
+  "but not"
+] @operator
+
+[
+  "model"
+  "schema"
+  "type"
+  "relations"
+  "define"
+  "from"
+] @keyword
+
+"condition" @keyword.function
+
+(comment) @comment