Improve keyword normalization

[hukkin]

This PR attempts to improve keyword normalization in a few ways:

• Lower case keywords in emojis.json. There are upper case letters in the data that are otherwise not searchable. With this e.g this works.

  $ em -s åland
  Copied! 🇦🇽  flag_aland_islands

  Main branch would currently return no results because the letter "å" is upper cased in emojis.json.
• Normalize dashes (-) in emojis.json. They are already normalized in user input. This makes keywords such as blue-square searchable. Dashes are almost exclusively used as word separator in keywords, so normalization makes sense.
• Don't normalize dots (.) in user input. They aren't normalized in emojis.json so are not searchable in main branch without this. This makes more sense than normalizing in emojis.json too, IMO, because dots are not used as a word separator in emojis.json unlike spaces, dashes and underscores, but only as part of abbreviations such as "mr.", "mrs.", "st.", "u.s.". This much improves searches such as

  $ em -s st.
  🇧🇱  flag_st_barthelemy
  🇫🇷  flag_france
  🇰🇳  flag_st_kitts_nevis
  🇱🇨  flag_st_lucia
  🇲🇫  flag_st_martin
  🇵🇲  flag_st_pierre_miquelon
  🇸🇭  flag_st_helena
  🇻🇨  flag_st_vincent_grenadines

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.56%. Comparing base (6eb4993) to head (59f52c4).
Report is 2 commits behind head on main.

Additional details and impacted files

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##             main     #164   +/-   ##
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  Coverage   95.56%   95.56%           
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  Files           2        2           
  Lines         203      203           
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  Hits          194      194           
  Misses          9        9           

Flag	Coverage Δ
macos-latest	92.61% <100.00%> (ø)
ubuntu-latest	93.10% <100.00%> (ø)
windows-latest	92.61% <100.00%> (ø)

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[hugovk]

Thank you!

Do you think you'll have some more improvements or shall we do a release? No rush either way :)

[hukkin]

Thanks for having the time to review all of these. I don't have any more improvements planned right now.

A release sounds good, but also no rush!