Update Doc/library/enum.rst

Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>

Author: guoci

Doc/library/enum.rst

@@ -1044,7 +1044,7 @@ Utilities and Decorators
 
    Like built-in :func:`bin`, except negative values are represented in
    two's-complement, and the leading bit always indicates sign
-   (0=positive, 1=negative).
+   (``0`` implies positive, ``1`` implies negative).
 
       >>> import enum
       >>> enum.bin(10)