Documentation Mapping Results SWMM - wrong links to images

[Stefan]

In the documentation two links to the images are wrong and the images do not display because their ending is .JPG instead of .jpg

https://github.com/QGEP/docs/blob/master/en/qgep_swmm/Mapping.rst

I suggest to rename all files with lower case in the filename and ending: https://github.com/QGEP/docs/tree/master/en/qgep_swmm/images to avoid this kind of errors.