feat: add autocomplete and type inference

[justintime4tea]

Adds autocomplete to config.get and type
inference to the value assigned.

Auto-complete works under JavaScript, REPL, and
TypeScript. JavaScript users can continue to use
the Config constructor method but must switch
to using the createConfig helper method to
enjoy auto-complete.

Auto-Complete Example:
If you type config.get('<tab> you'll see a list
of suggested values that come directly from
whatever was configured by the user in their
config.js.

Type Inference Example:
If you've configured "port" to be a number in
config.js and assign a variable like so:
const port = config.get('port')
The variable "port" will be inferred to be a number.

Ref: NA

[biblicalph]

So autocomplete is enabled by the type system correct?

[justintime4tea]

So autocomplete is enabled by the type system correct?

Yes, indeed. The "typings" file index.d.ts describes a param for config.get who's valid values and returned value types, are derived from what the user creates in their <Config/Env> ie: config.js.

[esatterwhite]

Generally for open source things we want to target functionality that works with out extraneous tooling or that makes assumptions about a developers workflow. It should work with stock node. even in the REPL

in this case that would be typescript or vscode/typescript-language-server.

while this is generally fine to add, it doesn't work for everyone or in all cases
How could would make something like this work w/o those tools?

[justintime4tea]

That's a great call-out!

We should also rename Env, within index.js, to be Config. If we refrain from assumptions around tooling, as you suggest, we have the case where someone is using TypeScript, and it's confusing to have to "alias" Env to Config within source code during import. A solution to this confusion, that would fit both JavaScript and TypeScript and remove existing assumptions (ie: only JS users), would be to rename Env to Config within index.js.

[justintime4tea]

I've updated my contribution to be inclusive of vanilla JavaScript, and REPL, users and renamed Env to Config to reduce confusion and be more inclusive of TypeScript users who don't wish to alias the import.

[justintime4tea]

I updated the CHANGELOG.md but I'm not sure how to add the commit hash referenced by the bullet points. I guess this can happen once it's been merged and a new release is tagged? I'm assuming this is typically an "after the merge" step but I wanted to preemptively add the changelog so there's less work "upstream". I can totally remove the CHANGELOG bits if needed or apply any other suggested changes.

Nevermind :)