Added more documentation

8 jobs for FixPystencilUpdate in 43 minutes and 35 seconds (queued for 2 seconds)
Name Stage Failure
build-documentation Test
writing output... [ 90%] sphinx/scenarios
writing output... [ 93%] sphinx/stencils
writing output... [ 96%] sphinx/tutorials
writing output... [100%] sphinx/zbibliography

Warning, treated as error:
/builds/pycodegen/lbmpy/lbmpy/ of lbmpy.creationfunctions:11:'any' reference target not found: lbmpy.enums.Stencil
Cleaning up file based variables
ERROR: Job failed: exit code 1