Make the definition of the width more explicit that it includes any
extra signs added by other options.
https://bugs.python.org/issue38657
Automerge-Triggered-By: @Mariatta
.. versionchanged:: 3.6
Added the ``'_'`` option (see also :pep:`515`).
-*width* is a decimal integer defining the minimum field width. If not
-specified, then the field width will be determined by the content.
+*width* is a decimal integer defining the minimum total field width,
+including any prefixes, separators, and other formatting characters.
+If not specified, then the field width will be determined by the content.
When no explicit alignment is given, preceding the *width* field by a zero
(``'0'``) character enables