DOC: clean up some doc-build warnings

[jreback]

No description provided.

[jreback]

so @jorisvandenbossche all of those nasty warnings just needed a blank line before AND after a list when embedded in a doc-string. very confusing message

[jorisvandenbossche]

Yes, indeed, that's the rule for rst lists and also apply in docstrings, unless it's the only thing in the explanation of a parameter (no text before or after in the entry), then no blank lines are needed (eg in this case it is normally not needed)

[jreback]

ok I fixed, but that seems a confusing rule. better to just put blanks around lists in doc-strings always, no? (checking if taking these out still has warnings). I was trying things so didn't always take out the added whitespace.

[jreback]

only big ones left are these

/Users/jreback/pandas/doc/source/generated/pandas.Series.str.partition.rst:6: WARNING: don't know which module to import for autodocumenting u'Series.str.partition' (try placing a "module" or "currentmodule" directive in the document, or giving an explicit module name)
/Users/jreback/pandas/doc/source/generated/pandas.Series.str.repeat.rst:6: WARNING: don't know which module to import for autodocumenting u'Series.str.repeat' (try placing a "module" or "currentmodule" directive in the document, or giving an explicit module name)

and one on groupby.nth I can't seem to figure out...

[jorisvandenbossche]

In the list above, the extra indentation for the list is also not needed

[jorisvandenbossche]

On the groupby.nth, I also already looked at before, but didn't spot the error either

[jreback]

merged via fcab956