New rt and rf abbrevations for return true; and return false;

[japplis]

This is a pull request for 2 new code templates in NetBeans:

• rt for "return true;"
• rf for "return false;"

Reasons:

• Both are used quite often. For example NetBeans source code has more than 14,000 "return true;" and more than 20,000 "return false;"
• They are consistent with the following existing code template in NetBeans: "re" for "return" and "rn" for "return null;"
• Easy to remember: just like rn for return null; 't' for true and 'f' for false
• Easy to use: rt and rf are next each other on the keyboard
• I've been using these code templates for at least 2 years and they remain ones of the main code templates I use

[lkishalmi]

Looks sane to me.

Thanks for your contribution!

[matthiasblaesing]

Looks sane