Add nix language syntax (#2024)

* Create nix.yaml

Add nix language syntax

* Add nix-linter

runtime/syntax/nix.yaml

@@ -0,0 +1,27 @@
+filetype: nix
+
+detect:
+    filename: "\\.nix$"
+
+rules:
+    - special: "\\b(Ellipsis|null|self|super|true|false|abort)\\b"
+    - statement: "\\b(let|in|with|import|rec|inherit)\\b"
+    - symbol.operator: "([~^.:;,+*|=!\\%@]|<|>|/|-|&)"
+    - symbol.brackets: "([(){}]|\\[|\\])"
+
+    - constant.number: "\\b[0-9](_?[0-9])*(\\.([0-9](_?[0-9])*)?)?(e[0-9](_?[0-9])*)?\\b"
+
+    - constant.string:
+        start: "\""
+        end: "\""
+        rules: []
+
+    - constant.string:
+        start: "''"
+        end: "''"
+        rules: []
+
+    - comment:
+        start: "#"
+        end: "$"
+        rules: []