Update docs for string.zfill
diff --git a/Doc/library/string.rst b/Doc/library/string.rst
index a7336c4..1a39ca9 100644
--- a/Doc/library/string.rst
+++ b/Doc/library/string.rst
@@ -1025,8 +1025,9 @@
.. function:: zfill(s, width)
- Pad a numeric string on the left with zero digits until the given width is
- reached. Strings starting with a sign are handled correctly.
+ Pad a numeric string *s* on the left with zero digits until the
+ given *width* is reached. Strings starting with a sign are handled
+ correctly.
.. function:: replace(s, old, new[, maxreplace])