Add compat for BigInt

[VFDan]

The BigInt compatibility table is needed:

• I added a compatibility table for BigInt.
• The CanIUse: https://caniuse.com/#feat=bigint
  Sorry, the file should be in the javascript/builtins/ folder.

[jpmedley]

Thank you for your help on this.

[VFDan]

I added a commit to fix the errors.

[VFDan]

I added a commit with the Node.js compatibility, and put it in the correct folder

[VFDan]

I un-localized the URL.

[ddbeck]

A couple style fixes and this will be ready to merge. Thank you for your help on this, @VFDan!

[VFDan]

I added a commit with those style changes.

[VFDan]

Travis CI says: "

  File : javascript/builtins/BigInt.json
  Style – Error on line #1
    Actual:   {
    Expected: {

"
But when I look at the file, there is nothing to the left of the {. I tried to backspace, but it did nothing.

[ddbeck]

It appears that your line endings aren't just new lines (i.e., your line endings are Windows rather than Unix style). I've opened PR #3231 to highlight this better. In the mean time, there's probably an option in your editor to convert line endings, which should fix the problem.

[VFDan]

I changed the line endings (I said Unicode but meant Unix). Travis CI said the same thing. Maybe there is a bug with Travis CI, because I changed the line endings

Fixed!

[ddbeck]

@VFDan I went ahead and fixed the line endings directly (and unnoticed tabs vs spaces issue). I don't know why that had to be such a hassle, but hopefully #3231 will avoid that in the future. I'll be merging your contribution shortly. Thank you! 🎉

[VFDan]

Thank you for merging the commits! I'm also on MDN under the username VFDan.

[VFDan]

I put the compatibility table in the MDN BigInt page.