chore($locale): add quotation marks to reserved keyword "short"

Although the "short" keyword was pulled as a reserved word from ES5, compilers like
YUICompressor still treat it as reserved and may break.

See 7.6.1.1 of ES5 spec for updated reserved words: http://www.ecma-international.org/publications/files/ECMA-ST-ARCH/ECMA-262%205th%20edition%20December%202009.pdf

Closes #5320