Add isInstanceOf(value, classNameOrClass)

[jcbhmr]

fixes #36
This PR would...

• add isInstanceOf() source
• have a JSDoc comment describing what it does
• add a test case to the test file

[mesqueeb]

@jcbhmr
Can you add something on isInstanceOf to the readme? and above the ### Getting and checking for specific types section.
Will open a new issue for this.

---

for the JSDocs on the overloads I meant this:

but i guess this is pretty rare that people click that button and it's better to keep it non-duplicated I guess!

[jcbhmr]

for the JSDocs on the overloads I meant this:

Ahh! I see what you mean now! 👍

For reference, the official TypeScript way of doing it is: https://github.com/microsoft/TypeScript/blob/main/src/lib/es2023.array.d.ts#L2-L12

so I don't think it's that big of a deal when the official TS lib.d.ts files are just a single JSDoc comment 🤷‍♀️