I do agree that having ‘Discourse’ in there is also a little redundant/repetitive, but it’s to offset the brevity of the single word titles (and is also often the name of the plugin). We have dropped the preceding ‘Discourse’ from the /plugins page for better readability, but it doesn’t have the same effect in a topic list.
I think including it and having it first is the lesser of all the evils. It is a shame search can’t pick up on the category and tag signals I’m laying out for it, but if we really need to stuff the title with ‘plugin’ to make it work then so be it. 
It’d be good if I could set a ‘pinned result’ for certain keywords. That way the instructions would always be top of the tree.