Add rsplit method for str and unicode builtin types.
SF feature request #801847.
Original patch is written by Sean Reifschneider.
diff --git a/Doc/lib/libstring.tex b/Doc/lib/libstring.tex
index 3f902cf..11054e2 100644
--- a/Doc/lib/libstring.tex
+++ b/Doc/lib/libstring.tex
@@ -215,6 +215,23 @@
elements).
\end{funcdesc}
+\begin{funcdesc}{rsplit}{s\optional{, sep\optional{, maxsplit}}}
+ Return a list of the words of the string \var{s}, scanning \var{s} from
+ the end working forward. The resulting list of words is in the same
+ order as \function{split()}. If the optional second argument \var{sep}
+ is absent or \code{None}, the words are separated by arbitrary strings
+ of whitespace characters (space, tab, newline, return, formfeed).
+ If the second argument \var{sep} is present and not \code{None}, it
+ specifies a string to be used as the word separator. The returned
+ list will then have one more item than the number of non-overlapping
+ occurrences of the separator in the string. The optional third argument
+ \var{maxsplit} defaults to 0. If it is nonzero, at most \var{maxsplit}
+ number of splits occur, and the remainder of the string is returned
+ as the first element of the list (thus, the list will have at most
+ \code{\var{maxsplit}+1} elements).
+ \versionadded{2.4}
+\end{funcdesc}
+
\begin{funcdesc}{splitfields}{s\optional{, sep\optional{, maxsplit}}}
This function behaves identically to \function{split()}. (In the
past, \function{split()} was only used with one argument, while