Add a specific mention of the term "operator overloading" and add an
index entry. Suggested to python-docs.
diff --git a/Doc/ref/ref3.tex b/Doc/ref/ref3.tex
index 86c9cea..fe628e0 100644
--- a/Doc/ref/ref3.tex
+++ b/Doc/ref/ref3.tex
@@ -939,7 +939,10 @@
A class can implement certain operations that are invoked by special
syntax (such as arithmetic operations or subscripting and slicing) by
-defining methods with special names. For instance, if a class defines
+defining methods with special names.\indexii{operator}{overloading}
+This is Python's approach to \dfn{operator overloading}, allowing
+classes to define their own behavior with respect to language
+operators. For instance, if a class defines
a method named \method{__getitem__()}, and \code{x} is an instance of
this class, then \code{x[i]} is equivalent to
\code{x.__getitem__(i)}. Except where mentioned, attempts to execute