Require a line break after an unknown preprocessor directive

grammar.js

@@ -104,7 +104,8 @@ module.exports = grammar({
 
     preproc_call: $ => seq(
       $.preproc_directive,
-      $.preproc_arg
+      optional(seq(/[ \t]+/, $.preproc_arg)),
+      '\n'
     ),
 
     preproc_if: $ => seq(

src/grammar.json

@@ -292,8 +292,29 @@
           "name": "preproc_directive"
         },
         {
-          "type": "SYMBOL",
-          "name": "preproc_arg"
+          "type": "CHOICE",
+          "members": [
+            {
+              "type": "SEQ",
+              "members": [
+                {
+                  "type": "PATTERN",
+                  "value": "[ \\t]+"
+                },
+                {
+                  "type": "SYMBOL",
+                  "name": "preproc_arg"
+                }
+              ]
+            },
+            {
+              "type": "BLANK"
+            }
+          ]
+        },
+        {
+          "type": "STRING",
+          "value": "\n"
         }
       ]
     },