Currently when a prepend-path, append-path or module use target a path entry that is already defined in the environment variable, its value is not updated.

A configuration option may be introduced to update the order of entries, for instance on a prepend-path to move the path entry at the first position.

This is the behavior used by default on Lmod. And Lmod has LMOD_TMOD_PATH_RULE to set the behavior like on Modules.

This topic was approached long ago on #60.