Make 'line_comment' more explicit about newlines

Because of the way regular expressions work, they were already bounded
at newlines here, but explicit is better than implicit :-).

grammar.js

@@ -23,7 +23,7 @@ module.exports = grammar({
       $.module,
     ),
 
-    line_comment: (_) => seq("//", /.*/),
+    line_comment: (_) => seq("//", /[^\n]*/),
 
     block_comment: (_) => seq("/*", /[^*]*\*+([^/*][^*]*\*+)*/, '/'),
 

src/grammar.json

@@ -30,7 +30,7 @@
         },
         {
           "type": "PATTERN",
-          "value": ".*"
+          "value": "[^\\n]*"
         }
       ]
     },

test/corpus/comments.txt

@@ -85,6 +85,23 @@ Block comment with asterisks
 
 --------------------------------------------------------------------------------
 
+(source_file
+  (block_comment))
+
+================================================================================
+Block comment (multiline)
+================================================================================
+
+/*
+    This
+    is
+    a
+    long
+    comment
+*/
+
+--------------------------------------------------------------------------------
+
 (source_file
   (block_comment))