The argument is called static_members, not static_fields.
gdb/doc/ChangeLog:
2020-11-29 Hannes Domani <ssbssa@yahoo.de>
PR python/26974
* python.texi: Fix docu for static members argument.
+2020-11-29 Hannes Domani <ssbssa@yahoo.de>
+
+ PR python/26974
+ * python.texi: Fix docu for static members argument.
+
2020-11-19 Andrew Burgess <andrew.burgess@embecosm.com>
* gdb.texinfo (Debugging Output): Document 'set/show debug
the @emph{declared} type should be used. (See @code{set print object} in
@ref{Print Settings}).
-@item static_fields
+@item static_members
@code{True} if static members should be included in the string
representation of a C@t{++} object, @code{False} if they shouldn't (see
@code{set print static-members} in @ref{Print Settings}).