document methods that don't work with :content_file libwww-perl#219

Changes

@@ -1,6 +1,8 @@
 Revision history for WWW::Mechanize
 
 {{$NEXT}}
+    [DOCUMENTATION]
+    - Document methods that don't work with :content_file (GH#219) (Julien Fiegehenn)
 
 2.05      2021-09-21 14:06:00Z
     - Update docs for protocols_allowed and protocols_forbidden (GH#323) (Olaf

lib/WWW/Mechanize.pm

@@ -438,6 +438,25 @@ B<NOTE:> Because C<:content_file> causes the page contents to be
 stored in a file instead of the response object, some Mech functions
 that expect it to be there won't work as expected. Use with caution.
 
+Here is a non-complete list of methods that do not work as expected with
+C<:content_file>:
+C< L<< forms()|/"$mech->forms()" >> >,
+C< L<< current_form()|/"$mech->current_form()" >> >,
+C< L<< links()|/"$mech->links()" >> >,
+C< L<< title()|/"$mech->title()" >> >,
+C< L<< content(...)|/"$mech->content(...)" >> >,
+C< L<< text()|/"$mech->text()" >> >,
+all L<< content-handling methods|/"CONTENT-HANDLING METHODS" >>,
+all L<< link methods|/"LINK METHODS" >>,
+all L<< image methods|/"IMAGE METHODS" >>,
+all L<< form methods|/"FORM METHODS" >>,
+all L<< field methods|/"FIELD METHODS" >>,
+C< L<< save_content(...)|/"$mech->save_content( $filename, %opts )" >> >,
+C< L<< dump_links(...)|/"$mech->dump_links( [[$fh], $absolute] )" >> >,
+C< L<< dump_images(...)|/"$mech->dump_images( [[$fh], $absolute] )" >> >,
+C< L<< dump_forms(...)|/"$mech->dump_forms( [$fh] )" >> >,
+C< L<< dump_text(...)|/"$mech->dump_text( [$fh] )" >> >
+
 =cut
 
 sub get {