HtmlDiff corrections from Dan Gass, + trimmed trailing whitespace.

Doc/lib/libdifflib.tex

@@ -77,9 +77,10 @@
     wrapped.
 
     \var{linejunk} and \var{charjunk} are optional keyword arguments passed
-    into \code{ndiff()} (used to by \class{HtmlDiff} to generate the 
+    into \code{ndiff()} (used by \class{HtmlDiff} to generate the
     side by side HTML differences).  See \code{ndiff()} documentation for
     argument default values and descriptions.
+
   \end{funcdesc}
 
   The following methods are public:
@@ -121,8 +122,10 @@
     documentation.
   \end{funcdesc}
 
-  \file{Tools/scripts/ndiff.py} is a command-line front-end to this class
+  \file{Tools/scripts/diff.py} is a command-line front-end to this class
   and contains a good example of its use.
+
+  \versionadded{2.4}
 \end{classdesc*}
 
 \begin{funcdesc}{context_diff}{a, b\optional{, fromfile\optional{, tofile