Add support for ARM constant notation in GAS lexer
Add support for ARM constant notation in GAS lexer

GNU supports ARM syntax which uses notation like #1 for constants.
Currently this is handled like a comment which is incorrect.

Take the case of:
ldr     r0, [r1, #0]

Right now the #0] would be treated like a comment and looks
very poor.

Was referenced in issue #627

Signed-off-by: Brennan Ashton <3c2365aa085787349a5327558db844b55eabde30@brennanashton.com>

dscorbett/pygments,pygments/pygments,pygments/pygments,dscorbett/pygments,pygments/pygments,dscorbett/pygments,pygments/pygments,pygments/pygments,pygments/pygments,pygments/pygments,dscorbett/pygments,pygments/pygments,pygments/pygments,dscorbett/pygments,dscorbett/pygments,dscorbett/pygments,dscorbett/pygments,dscorbett/pygments,pygments/pygments,dscorbett/pygments,dscorbett/pygments,pygments/pygments,dscorbett/pygments,dscorbett/pygments,pygments/pygments,pygments/pygments,pygments/pygments,pygments/pygments,dscorbett/pygments,pygments/pygments,dscorbett/pygments,pygments/pygments,pygments/pygments,dscorbett/pygments,dscorbett/pygments,dscorbett/pygments