compiler/glsl: clean up output

It's really hard to make sure we have the right amount of %s in the
format string, so let's change how we generate this string.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9896>
1 file changed