Spelling fixes e to i.

utils/peg/pegparser.dart

Index: utils/peg/pegparser.dart
diff --git a/utils/peg/pegparser.dart b/utils/peg/pegparser.dart
index 69292b6002be6593f2e0d83dfce26168483bc43e..a5fb3bbe6bb974f47fb3dcaefd3881270a6cdce4 100644
--- a/utils/peg/pegparser.dart
+++ b/utils/peg/pegparser.dart
@@ -146,7 +146,7 @@ _Rule TEXT(rule, [extractor]) => new _TextValueRule(
  * If [rule] is value generating then the value is the value generated by [rule]
  * if it matches, and [:null:] if it does not.
  *
- * If [rule] is not value generatinge then the value is [:true:] if [rule]
+ * If [rule] is not value generating then the value is [:true:] if [rule]
  * matches and [:false:] if it does not.
  */
 _Rule MAYBE(rule) => new _OptionalRule(_compile(rule));