Revert "[New] support enumerable Symbol properties"

[MartyJRE]

This reverts commit 7d659e7.

The reason for this is that the new feature is a breaking change and should be versioned as such.

Fixes #5.

[ljharb]

A naive revert isn't the best solution here; it'd be to put the symbol part behind an option (ie, (includeSymbols ? ownEnumerableKeys : objectKeys) everywhere ownEnumerableKeys is currently called)

[MartyJRE]

@ljharb I added options to traverse. It now only deals with string keys by default. When given includeSymbols: true inside the options, it functions the way you desgined.

Also added immutable to options to avoid having too many parameters.

[ljharb]

(you'll also need to rebase; i pulled out the immutable → options refactor)

[MartyJRE]

@ljharb I changed the jsdocs as requested, check for the existance of higher order, otherwise, the code uses native javascript. Rebased your changes, the tests run successfully, all should be good.

[MartyJRE]

The Automatic Rebase / _ / Automatic Rebase (pull_request_target) job still seems to think there are conflicts.
However, when I try to merge locally, there are no conflicts to be seen.

[ljharb]

Don’t worry about the automatic rebase workflow; it’s failing because you made your PR from “main”.

[ljharb]

I've rebased this and condensed it down to one commit.

It's still failing 3 tests for me, and I'm not sure why.

[ljharb]

@MartyJRE are you able to complete this PR? i'd like to get the fix released.

[MartyJRE]

@ljharb seems I accidentally added a ! in one condition, the change should be good to go now