Fix comment containing backslash

corpus/expressions.txt

@@ -437,3 +437,16 @@ Comments with escaped newlines
 
 (translation_unit
   (comment))
+
+==============================================
+Comments with escaped chars and newlines
+==============================================
+
+// one \a \b \
+   two
+// one \c \d
+---
+
+(translation_unit
+  (comment)
+  (comment))

grammar.js

@@ -763,7 +763,7 @@ module.exports = grammar({
 
     // http://stackoverflow.com/questions/13014947/regex-to-match-a-c-style-multiline-comment/36328890#36328890
     comment: $ => token(choice(
-      seq('//', /(\\[.\n]|[^\\\n])*/),
+      seq('//', /(\\(.|\n)|[^\\\n])*/),
       seq(
         '/*',
         /[^*]*\*+([^/*][^*]*\*+)*/,

src/grammar.json

@@ -4439,7 +4439,7 @@
               },
               {
                 "type": "PATTERN",
-                "value": "(\\\\[.\\n]|[^\\\\\\n])*"
+                "value": "(\\\\(.|\\n)|[^\\\\\\n])*"
               }
             ]
           },