Consistify spelling of realm

[annevk]

There's Realm and realm, JavaScript Realm and JavaScript realm, and various others.

https://tc39.es/ecma262/#realm is lowercase. Should we align with that? The exception here would be internal slots, but I think we can safely lowercase the remainder.

Also, do we generally want to use JavaScript realm or just realm?

(Stumbled across this due to whatwg/fetch#1343 which could still be changed.)

[domenic]

Good catch.

The difference between "realm" and "Realm": the latter is supposed to refer to the concrete specification type, more properly known as a "Realm Record". The former is more about the concept. Having both is probably not necessary. I guess I prefer "realm" > "Realm Record " > "Realm".

I kind of like the clarity of the JavaScript prefix, but I don't think its really worth keeping. Prefixing external concepts with their spec names is pretty rare, and nothing else is using the term "realm".

So my vote is for s/(?:JavaScript )?[Rr]ealm(?: Record)?/realm/g, including in the definitions of existing concepts.

A potential wrinkle is that the JS spec defines "the current Realm Record" (which we seem to always refer to without the "the" prefix). Maybe we can alias it to "current realm" as part of importing it.