GPU page, add missing information on modules

I think, there should be at least one more sentence at the very beginning of the GPU page on modules:

https://gitlab.hrz.tu-chemnitz.de/zih/hpcsupport/hpc-compendium/-/blob/preview/doc.zih.tu-dresden.de/docs/software/gpu_programming.md?ref_type=heads&plain=1#L7

If not, remove the colon at the end of this sentence.