tests: Add a test case for functions having a rename-to annotation

https://bugzilla.gnome.org/show_bug.cgi?id=710478
gtkdoc-mkdb: Don't complain about annotations with other chars

Certain annotations like 'allow-none' have hyphens in them.
Others like 'rename_to symbol_name_1' have numbers and underscores
Fix gtkdoc-mkdb complaints about such annotations

https://bugzilla.gnome.org/show_bug.cgi?id=710478