doc: reword testing guide paragraph

The commit 2b5293a added the
Mojolicious::Lite testing snippet that loads the application from a
file as an alternative to the snippet before that. However, the
paragraph that explains the details for both snippets explicitly
mentions the 'Frogs' application, which is used only in the first
snippet, creating a possible confusion for some readers that may wonder
if that explanation is also valid for the Mojolicious::Lite snippet.

This patch removes the explicitly mention of 'Frogs' from the paragraph
and also make change the 'This object initializes' to 'The object
initializes' to give a more generic meaning, including both snippets.

lib/Mojolicious/Guides/Testing.pod

@@ -159,9 +159,9 @@ To test a L<Mojolicious::Lite> application, pass the file path to the applicatio
   use Mojo::File qw(curfile);
   my $t = Test::Mojo->new(curfile->dirname->sibling('myapp.pl'));
 
-This object initializes a L<Mojo::UserAgent> object, loads the Mojolicious application C<Frogs>, binds and listens on a
-free TCP port (e.g., 32114), and starts the application event loop. When the L<Test::Mojo> object (C<$t>) goes out of
-scope, the application is stopped.
+The object initializes a L<Mojo::UserAgent> object, loads the Mojolicious application, binds and listens on a free TCP
+port (e.g., 32114), and starts the application event loop. When the L<Test::Mojo> object (C<$t>) goes out of scope, the
+application is stopped.
 
 Relative URLs in the test object method assertions (C<get_ok>, C<post_ok>, etc.) will be sent to the Mojolicious
 application started by L<Test::Mojo>: