remember which Mojo::DOM we are using

[plicease]

This adds a little state to the Decode::Mojo plugin, and will hopefully help out with schizophrenic weridisms like this maybe:

Output from './Build':

Can't locate Mojo/DOM58.pm in @INC (you may need to install the Mojo::DOM58 module) (@INC contains: inc inc /opt/perl-5.31.8/lib/site_perl/5.31.8/x86_64-linux /opt/perl-5.31.8/lib/site_perl/5.31.8 /opt/perl-5.31.8/lib/5.31.8/x86_64-linux /opt/perl-5.31.8/lib/5.31.8 .) at /opt/perl-5.31.8/lib/site_perl/5.31.8/Alien/Build.pm line 306.
Building Acme-Alien-DontPanic2
Alien::Build::Plugin::PkgConfig::Negotiate> Using PkgConfig plugin: PkgConfig::CommandLine