allow more env paths

corpus/shebang.txt

@@ -28,7 +28,6 @@ nix-shell shebang no env
 (source_file
   (first_line))
 
-
 ==================
 nix-shell shebang whitespace no env
 ==================
@@ -38,3 +37,23 @@ nix-shell shebang whitespace no env
 
 (source_file
   (first_line))
+
+==================
+nix-shell shebang via relative env
+==================
+
+#!env nix-shell
+---
+
+(source_file
+  (first_line))
+
+==================
+nix-shell shebang via /bin/env
+==================
+
+#!/bin/env nix-shell
+---
+
+(source_file
+  (first_line))

grammar.js

@@ -47,8 +47,11 @@ module.exports = grammar({
     ),
 
     _shebang_open: $ => '#!',
-    // TODO: allow `usr/bin/env`, `env`
-    _env: $ => '/usr/bin/env',
+    _env: $ => choice(
+      '/usr/bin/env',
+      '/bin/env',
+      'env',
+    ),
     _nix_shell: $ => 'nix-shell',
     _ws: $ => / +/,
     _opt_ws: $ => / */,