Fixed small errors in readme.

2 jobs for !122 with n2sd_dataset_generator in 37 seconds (queued for 2 seconds)
detached
Status Job ID Name Coverage
  Test
failed #8456
pages

00:00:24

passed #8455
spelling

00:00:12

 
Name Stage Failure
failed
pages Test There is an unknown failure, please try again
  File "/usr/local/lib/python3.6/logging/__init__.py", line 719, in filter
result = f.filter(record)
File "/usr/local/lib/python3.6/site-packages/sphinx/util/logging.py", line 410, in filter
raise SphinxWarning(location + ":" + message)
sphinx.errors.SphinxWarning: /builds/pgeiger/E-CAM-Library/Classical-MD-Modules/modules/nn_structure_detection/n2sd_dataset_generator/readme.rst:document isn't included in any toctree

Warning, treated as error:
/builds/pgeiger/E-CAM-Library/Classical-MD-Modules/modules/nn_structure_detection/n2sd_dataset_generator/readme.rst:document isn't included in any toctree
ERROR: Job failed: exit code 1