Fixed typo in navigator.dart doc comments (#12995)
Fixed typo in navigator.dart doc comments (#12995)


flutter/flutter,cbracken/flutter,cbracken/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,Hixie/flutter,Hixie/flutter,Hixie/flutter,tvolkert/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter,Hixie/flutter,cbracken/flutter,tvolkert/flutter,cbracken/flutter,Hixie/flutter,Hixie/flutter,tvolkert/flutter,cbracken/flutter,Hixie/flutter,tvolkert/flutter,Hixie/flutter,tvolkert/flutter,cbracken/flutter,cbracken/flutter,Hixie/flutter,tvolkert/flutter,cbracken/flutter,Hixie/flutter,flutter/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,flutter/flutter,flutter/flutter,cbracken/flutter,flutter/flutter