Add docs for get_grouped_opcodes().

Doc/lib/libdifflib.tex

@@ -82,6 +82,8 @@
 
   \file{Tools/scripts/diff.py} is a command-line front-end for this
   function.
+
+  \versionadded{2.3}
 \end{funcdesc}  
 
 \begin{funcdesc}{get_close_matches}{word, possibilities\optional{,
@@ -213,6 +215,8 @@ emu
 
   \file{Tools/scripts/diff.py} is a command-line front-end for this
   function.
+
+  \versionadded{2.3}  
 \end{funcdesc} 
 
 \begin{funcdesc}{IS_LINE_JUNK}{line}
@@ -397,6 +401,17 @@ replace a[3:4] (x) b[2:3] (y)
 \end{verbatim}
 \end{methoddesc}
 
+\begin{methoddesc}{get_grouped_opcodes}{\optional{n}}
+  Return a generator of groups with up to \var{n} lines of context.
+
+  Starting with the groups returned by \method{get_opcodes()},
+  this method splits out smaller change clusters and eliminates
+  intervening ranges which have no changes.
+
+  The groups are returned in the same format as \method{get_opcodes()}.
+  \versionadded{2.3}			    
+\end{methoddesc}
+
 \begin{methoddesc}{ratio}{}
   Return a measure of the sequences' similarity as a float in the
   range [0, 1].