My source looks like this:
```
{ "pos": "+", "letters": [ "%", "`", "‰", "″" , "ⱼ", "ʲ", "⇔", "≅" ] },
```
The character `≅` _(«approximately equal to»)_ should be emitted when I press the `+` key with all three modifiers. But instead `≈` _(«almost equal to»)_ is emitted.
See also #28 for a similar issue. See also #24 for a proposed general solution.
For the special case of `≅` it appears to be an [error](https://gitlab.freedesktop.org/xorg/proto/xorgproto/-/commit/4901f35cac64d71ef295f4531af46c9b00eab1a8) in `keysymdef.h` and is now even [deprecated](https://gitlab.freedesktop.org/xorg/proto/xorgproto/-/commit/25f3278b85ec7d1c78bb150eaea52f9c98294ea4). I have updated the keysymdef output to fix it.
I have also changed my a bit with respect to the Unicode notation: it can be useful for readability and bugs like this, although the bugs shouldn't happen of course. I have added the possibility for notation like U+2248 that forces the Unicode output in e.g. XKB.