Allow spaces between the identifier and the translation when parsing ARB files

lib/src/icu_parser.dart

Index: lib/src/icu_parser.dart
diff --git a/lib/src/icu_parser.dart b/lib/src/icu_parser.dart
index c07934af42b0af4712b92a4b271f028b30413e9c..15c47b4e49c3c4be79d3b90a37bddd23b527f634 100644
--- a/lib/src/icu_parser.dart
+++ b/lib/src/icu_parser.dart
@@ -33,7 +33,7 @@ class IcuParser {
   get nonIcuMessageText => normalText.plus().map((x) => x.join());
   get twoSingleQuotes => string("''").map((x) => "'");
   get number => digit().plus().flatten().trim().map(int.parse);
-  get id => (letter() & (word() | char("_")).star()).flatten();
+  get id => (letter() & (word() | char("_")).star()).flatten().trim();
   get comma => char(",").trim();
 
   /**