Issue 15660: Clarify 0 prefix for width field in str.format doc.
diff --git a/Doc/library/string.rst b/Doc/library/string.rst
index ee6dbbc..0eda746 100644
--- a/Doc/library/string.rst
+++ b/Doc/library/string.rst
@@ -389,9 +389,9 @@
*width* is a decimal integer defining the minimum field width. If not
specified, then the field width will be determined by the content.
-If the *width* field is preceded by a zero (``'0'``) character, this enables
-zero-padding. This is equivalent to an *alignment* type of ``'='`` and a *fill*
-character of ``'0'``.
+Preceding the *width* field by a zero (``'0'``) character enables
+sign-aware zero-padding for numeric types. This is equivalent to a *fill*
+character of ``'0'`` with an *alignment* type of ``'='``.
The *precision* is a decimal number indicating how many digits should be
displayed after the decimal point for a floating point value formatted with