Remove unnecessary dynamic portion from the `plugin_action_links` filters

[johnbillion]

The plugin_action_links and plugin_action_links_{$plugin_file} filter names are prefixed with network_admin_ in the Network Admin Plugins list table. This makes the documentation for the filters unnecessarily verbose.

Let's remove the dynamic prefix from these filter names and apply the filters individually.

This has the side effect of allowing the @since docs for the network_admin_* filters to be corrected.

[johnbillion]

34117.diff​ looks complicated but all it's doing is removing the dynamic $prefix portion and replacing it with an if ( $screen->in_admin( 'network' ) ) { ... } else { ... } statement.

Indentation needs correcting before commit.

Drew, mind reviewing?

[DrewAPicture]

Docs fixes

[DrewAPicture]

@johnbillion I ended up just indenting the hooks since we're renaming them anyway. Our changelog style for renaming hooks (it's only happened about ~10 times before) is to mark the initial @since with "As hook_name", which I've done in 34117.2.diff​ among another minor fixes. Good to go.

[johnbillion]

In 34786:

Remove the unnecessary dynamic prefix used in the plugin_action_links filter name, and in those of its brethren. This way, network_admin_plugin_action_links gets listed as a separate filter.

Fixes #34117