feat(zig): basic treesitter support for zig. (#359)

* Add basic support for navigating zig files.

* Fix struct start position.

* Add test and tagged unions.

* Add test.

queries/zig/aerial.scm

@@ -0,0 +1,32 @@
+(Decl
+    (VarDecl
+      variable_type_function: (IDENTIFIER) @name
+      (#set! "kind" "Struct")
+      (_
+        (_
+          (ContainerDecl
+            (ContainerDeclType "struct") @symbol
+            ))))
+    )
+
+(Decl
+    (VarDecl
+      variable_type_function: (IDENTIFIER) @name
+      (#set! "kind" "Struct")
+      (_
+        (_
+          (ContainerDecl
+            (ContainerDeclType "union") @symbol
+            ))))
+    )
+
+(FnProto
+  function: (IDENTIFIER) @name
+  (#set! "kind" "Function")
+  ) @symbol
+
+
+(TestDecl
+  (STRINGLITERALSINGLE) @name
+  (#set! "kind" "Function")
+  ) @symbol

tests/symbols/zig_test.json

@@ -0,0 +1,62 @@
+[
+  {
+    "col": 0,
+    "end_col": 16,
+    "end_lnum": 1,
+    "kind": "Function",
+    "level": 0,
+    "lnum": 1,
+    "name": "myFunc",
+    "selection_range": {
+      "col": 3,
+      "end_col": 9,
+      "end_lnum": 1,
+      "lnum": 1
+    }
+  },
+  {
+    "col": 17,
+    "end_col": 23,
+    "end_lnum": 5,
+    "kind": "Struct",
+    "level": 0,
+    "lnum": 5,
+    "name": "MyStruct",
+    "selection_range": {
+      "col": 6,
+      "end_col": 14,
+      "end_lnum": 5,
+      "lnum": 5
+    }
+  },
+  {
+    "col": 22,
+    "end_col": 33,
+    "end_lnum": 9,
+    "kind": "Struct",
+    "level": 0,
+    "lnum": 9,
+    "name": "MyTaggedUnion",
+    "selection_range": {
+      "col": 6,
+      "end_col": 19,
+      "end_lnum": 9,
+      "lnum": 9
+    }
+  },
+  {
+    "col": 0,
+    "end_col": 1,
+    "end_lnum": 13,
+    "kind": "Function",
+    "level": 0,
+    "lnum": 11,
+    "name": "\"my test\"",
+    "selection_range": {
+      "col": 5,
+      "end_col": 14,
+      "end_lnum": 11,
+      "lnum": 11
+    }
+  }
+]

tests/treesitter/zig_test.zig

@@ -0,0 +1,13 @@
+fn myFunc() bool {
+    return true;
+}
+
+const MyStruct = struct {
+    is_true: bool,
+};
+
+const MyTaggedUnion = union(enum) { choice1, choice2 };
+
+test "my test" {
+    myFunc();
+}