Remove duplicate tests and filters

[felixfontein]

Fixes the ansible-core sanity test errors in ansible/ansible#78674 (comment).

[briantist]

This looks good to me, but what are aliases exactly? Are they just when filters/tests of different names use the same implementation? In the code comment, it looks for identical docs, which makes me wonder, how do we determine which is the "canonical" page?

[felixfontein]

This looks good to me, but what are aliases exactly? Are they just when filters/tests of different names use the same implementation?

Basically yes. (In ansible-core, symlinks are used to implement this for the documentation, and in the code the same function is exposed with different names.)

In the code comment, it looks for identical docs, which makes me wonder, how do we determine which is the "canonical" page?

Assuming that symlinks are used for the .yml files, the canonical version is the one whose name: coincides with the plugin's name. For example, in ansible-core's repo, lib/ansible/plugins/test/abs.yml has name: abs, and lib/ansible/plugins/test/is_abs.yml (symlink) also has name: abs.