libgnt/libgnt

Fix a bunch of issues with the docs.

2021-03-27, Gary Kramlich
89f1b7139a49
Fix a bunch of issues with the docs.

There's still three warnings but I'm having a hard time figuring out how to
fix them right now.

Testing Done:
Build the docs locally verified the warnings are gone.

Reviewed at https://reviews.imfreedom.org/r/586/
option('doc', type : 'boolean', value : true, yield : true,
description : 'build documentation with gtk-doc')
option('introspection', type : 'boolean', value : true, yield : true,
description : 'build introspection data')