Suppress relint errors in fortran.el

* lisp/progmodes/fortran.el (fortran-indent-to-column):
Suppress relint complaints about duplicated character in skip-set;
it's intentional and harmless.
1 job for master in 52 minutes and 30 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #2927
test-all

00:52:30