Following the raising of issue https://github.com/redhat-documentation/supplementary-style-guide/issues/213#issuecomment-1233033816 to request that the Red Hat and IBM style guides be updated to use "plugin" instead of the hyphenated form of "plug-in", it was agreed that "plugin" without the hyphen will be implemented in the SSG.

As such, all instances of "plug-in" must be updated to "plugin" in Quarkus documentation.