Don't use the return value of 'push'

Although 'push' returns the modified list, it isn't actually
documented to do so, so don't rely on it.

* lisp/emacs-lisp/rx.el (rx--translate-any): Add progn.
1 job for master in 55 minutes and 57 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
failed #4423
test-all

00:55:57

 
Name Stage Failure
failed
test-all Test
Makefile:319: recipe for target 'check-doit' failed
make[2]: Leaving directory '/builds/emacs/emacs/test'
make[2]: *** [check-doit] Error 1
Makefile:294: recipe for target 'check-expensive' failed
make[1]: *** [check-expensive] Error 2
make[1]: Leaving directory '/builds/emacs/emacs/test'
make: *** [check-expensive] Error 2
Makefile:959: recipe for target 'check-expensive' failed
ERROR: Job failed: exit code 1