Then we bypass all feed generation of both are set to None or throw a warning if SITEURL is unset.
Updated all documentation, to make sure the usage and warning is clear.
Most of the references to code and settings in the docs were wrapped
in single tickmarks (`), while reStructuredText syntax actually calls
for double tickmarks for inline literals, which are normally rendered
as monospaced text with spaces preserved. Converted the relevant
instances to inline literals, along with some other minor fixes.
