Remove non-existent icons from font

[stefan-korn]

It seems there are some invalid icon codes, anything like *-circle-1 and *-circle-fill-1. Should they be removed?

Fixes #1639

[Alex-Toucan]

Seems about right, with the invalid icons not existing.

[XhmikosR]

The icons are there, it's just something is going wrong with fantasticon.

[mdo]

Oh these look like duplicates. Those can probably get removed as suggested. I'll have to take a closer look.

[XhmikosR]

They cannot be removed because they are added again by fantasticon...

[XhmikosR]

I believe it's a bug in fantasticon that gets it confused because we have the same suffix or something like that.

BTW fantasticon v2.0.0 is completely broken on Windows: tancredi/fantasticon#470

Might be worth trying to rename the individual SVG files to see if the issue is fixed.

[mdo]

Yeah, these returned after removing them, so it's fantasticon is adding them back. Upgrading locally to v2.0.0 didn't help anything, so this might have to wait until we go v2 to do a rename of the icons.

[XhmikosR]

I made some progress here identifying the root cause. It seems the problem comes from using the previous codepoints. If I create the codepoints from start, then they are unique and as many as the icons.

I'll make a new issue, but removing these is moot unless fantasticon is fixed.

[XhmikosR]

Actually wait, this is the root cause.

[XhmikosR]

It seems there are more unused icons. I'll try to update your branch @stefan-korn but if you could do it that'd be awesome.

PS. Please don't commit the generated files; we only need the changes in bootstrap-icons.json in this PR.

[XhmikosR]

OK, I think I cleaned all of the non-existent icons. Would be nice if we had some kind of script to check for this in the future.