Improve the support of syntax highlighting groups

The implementation of syntax group support in EasyAlign is not very advanced and does not work in some cases.

Here I must digress for a moment and recommend the [SynGroup](https://stackoverflow.com/questions/9464844/how-to-get-group-name-of-highlighting-under-cursor-in-vim) function, which may be very useful in debugging this issue.

One thing that is not supported is _syntax group linking_ (`synIDtrans` vim function would help here). For example, in zsh syntax highlighting, the comments belong to a syntax group `zshComment` which is _linked_ to the `Comment` group. So, while the group is coloured as comments, it has a different name and hence the default EasyAlign `#` rules do not match it. I suspect this is the reason for most problems when using the `#` shortcut, such as #96.

And don't get me started on the case when the syntax highlighting is done by treesitter in neovim :) I don't thing that `synID*` functions work correctly at all in such case. OK, I understand that this is a vim plugin, but hey, it is year 2024 now !!!