adjustments to notification emails

[sigmundch]

I think it will be useful to:

• add the title of the issue in the subject of the notification email
• add the reporter in the body
• make the title of the issue stand out in the body somehow
• make the body of the issue separate (either by quoting or adding a separator)

For example, here is a before & after example from an issue I just got notified for.

Subject before:

dart-lang/sdk#24122 labeled Area-Dart2JS by floitschG

Suggested subject after:

[+Area-Dart2JS]: dart2js crashes when .packages contains same package name twice (#24122)

Body before:

User: floitschG - https://github.com/floitschG
Label: Area-Dart2JS

https://github.com/dart-lang/sdk/issues/24122
dart2js crashes when .packages contains same package name twice

stdout:
The compiler crashed: FormatException: Same package name occured
twice. (at offset 56)

0 parse (package:package_config/packages_file.dart:66:7)

1 Compiler.setupPackages. (package:compiler/src/apiimpl.dart:403:29)

...

Suggested body after:

Issue title: dart2js crashes when .packages contains same package name twice
Reported by hterkelsen
Area-Dart2JS added by floitschG

Original issue contents:

stdout:
The compiler crashed: FormatException: Same package name occured
twice. (at offset 56)

0 parse (package:package_config/packages_file.dart:66:7)

1 Compiler.setupPackages. (package:compiler/src/apiimpl.dart:403:29)

...

[kevmoo]

[sigmundch]

Thanks Kevin, new emails are awesome! :)