Allow BigInt usage in templates

What problem does this feature solve?

It would allow us to use numbers which is larger than MAX_SAFE_INTEGER.

What does the proposed API look like?

In HTML, {{BigInt("100")}}, {{100n}}, {{2n * 50n}} or {{50n + 50n}} should show “100” (it can be just simply string by using .toString()) at frontend. At the moment using BigInt in “Mustache” syntax just throw error. Sure, backup solution would be using external functions or converted into string and save it to variable. But using BigInt directly in HTML would be nice to have. More Information about BigInt -> https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt

[posva]

BigInt could be added to the other allowed variables like Number in templates. It will only be supported by browsers supporting it though

[lesleh]

BigInt has already good (still not large enough, Safari is still missing) cross browser support.

@YanDevDe Safari 14 beta now has BigInt support.