"Next quote" has disappeared!

I began trying to tweak the PHP code within wordpress because I was trying to change “quote” to “tesimonial”. I am the first to admit I should have looked at the documentation before doing anything. However, I have uninstalled and reinstalled the plugin, both via WP and manually, to no avail. The “Next quote” link has completely disappeared, even with the Ajax Refresh checkbox checked.

I don’t get why I am not given a fresh slate when I delete and then reinstall the plugin. Also the word I entered prior to deleting is remembered. Why is this? Is there some cache that needs to be cleared on the server or something?

Please help.

https://wordpress.org/plugins/quotes-collection/