Add support for PL/SQL

[supernovia]

Is your feature request related to a problem? Please describe

A user just wants to be able to add properly highlighted PL/SQL

Describe the solution you'd like

Add proper syntax highlighting for PL/SQL

Describe alternatives you've considered

I told them they could try choosing SQL for now. They were just using plain text. I tested with a few samples from this site with SQL selected, and some of it is picked up nicely, but other parts (print and what not for example) are not highlighting as one might expect:

Additional context

Here's the original request: https://wordpress.com/forums/topic/plsql-code-is-not-available-in-syntaxhighlighter-block/

The user had just selected text for now.