User Guide Minor fix

Sphinx was complaining about the "title overline" for the contributing page entry "Tips for a good issue report". Fixed this.
Signed-off-by:James L Parry <jim_parry@bcit.ca>
Enhance Language Class Writeup in User Guide (closes #674)

Added explanation for CodeIgniter's use of "idiom" versus standard abbreviations.
Provided additional examples as a guide.
Signed-off-by:James L Parry <jim_parry@bcit.ca>
Merge pull request #3360 from jim-parry/userguide/toc

User Guide Minor fix
Merge pull request #3361 from jim-parry/userguide/language

Enhance Language Class Writeup in User Guide (closes #674)