Improve the description of difflib in the documentation (GH-22253)

From "can produce difference information in various formats ..."
to " can produce information about file differences in various formats ..."

Automerge-Triggered-By: @Mariatta
diff --git a/Doc/library/difflib.rst b/Doc/library/difflib.rst
index 25e3511..aa08988 100644
--- a/Doc/library/difflib.rst
+++ b/Doc/library/difflib.rst
@@ -18,8 +18,8 @@
 --------------
 
 This module provides classes and functions for comparing sequences. It
-can be used for example, for comparing files, and can produce difference
-information in various formats, including HTML and context and unified
+can be used for example, for comparing files, and can produce information
+about file differences in various formats, including HTML and context and unified
 diffs. For comparing directories and files, see also, the :mod:`filecmp` module.