data: Update mdi icon references to newer code points

[mohkale]

CLOSES #20

nerd-fonts deprecated these legacy code points in v2.3.3 because they conflicted with non-Latin letters and then removed them in v3.0.0.

I updated the code-points by using expanding them into unicode, using nerdfix to pick the recommended replacement and then converting them back to escape sequences. I did this for both md and mdi but only mdi had actually changed so the diff shows it and no changes for md.

I took a look at a couple of the new mdi ones and looks like the existing font installed by nerd-icons.el already supports the new codepoints so nothing else should need to be updated.

Note: The following icons look to have been removed upstream and are have been removed by this PR as well:

• nf-mdi-venmo
• nf-mdi-martini
• nf-mdi-untappd
• nf-mdi-pharmacy
• nf-mdi-quicktime
• nf-mdi-dictionary
• nf-mdi-cisco_webex
• nf-mdi-nest_protect
• nf-mdi-book_unsecure
• nf-mdi-tumblr_reblog
• nf-mdi-do_not_disturb
• nf-mdi-amazon_clouddrive
• nf-mdi-do_not_disturb_off

[seagle0128]

It looks good for me! Let @rainstormstudio make the final call.