Add useFallback option

[ehmicky]

Fixes #100.

[sindresorhus]

What's the thinking of having it as a separate method rather than an option for replaceSymbols()? Just curious.

[ehmicky]

Not thinking about it! That's a better idea. :)

I updated the PR to use a useFallback boolean option instead. Please let me know if the name should be changed.

[sindresorhus]

Shouldn't these two show the same symbol since it's using the fallback no matter what?

[ehmicky]

Those two lines show the same symbol (the fallback one).

[sindresorhus]

The symbols look different to me:

[ehmicky]

Interesting. I am wondering whether we are looking at different sections. 🤔

Are those the ones in the main example section? Those should be different. The example in the TypeScript types should also show two different symbols.

On the other hand, the symbols in the example section for useFallback use the same Unicode codepoint in my text editor (U-221a). They display like so on Firefox:

[sindresorhus]

This is what I see: (Safari, macOS)

[ehmicky]

Wow, this challenged my sanity but I figured it out.

The first symbol was a single character with two codepoints: U+221a (tick) followed by U+FE0E (variation selection 15). Since the variation selector changes the aspect of the tick, both codepoints formed a single character.

On VSCode, when I looked up the unicode codepoint, it only showed me the first codepoint. But I used hexdump and saw the actual UTF-8 encoded codepoints.

I checked the other files, and it only happened in this example, and its copy in index.test-d.ts.

What happened is: the non-fallback tick is U+2714 followed by U+FE0E in the documentation (not the source code, I opened #102 to fix that). I ended up copying the variation selection around by mistake due to copy pasting.

So this is now fixed in b051c4e. 🪄

[ehmicky]

Fixed merged conflict.