How to rename current database?

I’m baffled that I have to sign up for a mailing list because I’m absolutely unable to figure out from the interface of
pgAdmin4 how to rename a given database? 

I’m going to the properties of the database to rename it, but get an error: ERROR: current database cannot be renamed.

Hmm, I guess it’s because it’s currently running, fine – I get that. But then, HOW THE HOLY CRAP DO I STOP THE DATABASE
SOI CAN RENAME IT!?!?!?!?!?!?!?!!?!!?!? 

Horrible experience from a user perspective.

How do I rename a current database in pgAdmin?

The docs are useless ...