Change line endings in comments to line_end (#219)

The /.*/ regex doesn't match any of the line endings recognized by the
JS RegExp engine, i.e. \n, \r, \u2028, \u2029. These are different from
the line endings supported by the rest of the Fluent Syntax. This change
unifies the line endings in all grammar productions.

spec/fluent.ebnf

@@ -16,7 +16,8 @@ Term                ::= "-" Identifier blank_inline? "=" blank_inline? Value Att
 
 /* Adjacent comment lines of the same comment type are joined together during
  * the AST construction. */
-CommentLine         ::= ("###" | "##" | "#") ("\u0020" /.*/)? line_end
+CommentLine         ::= ("###" | "##" | "#") ("\u0020" comment_char*)? line_end
+comment_char        ::= any_char - line_end
 
 /* Junk represents unparsed content.
  *

syntax/grammar.mjs

@@ -78,12 +78,18 @@ let CommentLine = defer(() =>
         maybe(
             sequence(
                 string(" "),
-                regex(/.*/).abstract)),
+                repeat(comment_char)
+                    .map(join).abstract)),
         line_end)
     .map(flatten(1))
     .map(keep_abstract)
     .chain(list_into(FTL.Comment)));
 
+let comment_char = defer(() =>
+    and(
+        not(line_end),
+        any_char));
+
 /* -------------------------------------------------------------------------- */
 /* Junk represents unparsed content.
  *

test/fixtures/cr.json

@@ -2,9 +2,8 @@
     "type": "Resource",
     "body": [
         {
-            "type": "Junk",
-            "annotations": [],
-            "content": "### This entire file uses CR as EOL.\r\rerr01 = Value 01\rerr02 = Value 02\r\rerr03 =\r\r    Value 03\r    Continued\r\r    .title = Title\r\rerr04 = { \"str\r\rerr05 = { $sel -> }\r"
+            "type": "ResourceComment",
+            "content": "This entire file uses CR as EOL.\r\rerr01 = Value 01\rerr02 = Value 02\r\rerr03 =\r\r    Value 03\r    Continued\r\r    .title = Title\r\rerr04 = { \"str\r\rerr05 = { $sel -> }\r"
         }
     ]
 }