Changed uses of assert to raise correct errors in combinat/root_system.
Trac #17086: GenericGraph's doc, __eq__, and __hash__ out of sync
fix typo
Use more illustrative test
Clarify comment as suggested by Nathann Cohen
Force weighted graph for path_semigroup
Mimic argument ordering of constructor
Simply pass weighted to constructor

This is instead of setting internal attribute _weighted, which might
bypass implementation-dependent setup for weighted/non-weighted.
More explicit about edge labels not being checked
Fix quotes in documentation
trac #17034: New user interface for orthogonal arrays and a .explain_construction method
trac #17034: Bugfix
Add __eq__ to documentation
trac #17034: documentation
Don't use "is" to compare strings
Change some exception types
trac #17034: Reviewer's remark
trac #17034: move the user functions into OAMainFunctions
Fix trivial documentation formatting errors in cachefunc.pyx

Insert a few missing {{{::}}} into docstrings modified in #16316.
Along the way, fix a few PEP8 issues, too.
trac #17086: Merged with #17092