Autocomplete improvements

[fonsp]

I would like to enable autocomplete on type (without having to press <TAB>), but it needs to be in a better shape before we do that :)

This PR makes some improvements and adds a setting to preview always on autocomplete

In this PR

• new browser setting PLUTO_TOGGLE_CM_AUTOCOMPLETE_ON_TYPE(true) to enable always on autocomplete
• don't autocomplete numbers
• enable complete_anyword for Identifiers only
• when autocompleting sqrt(, show a list of methods but ignore selecting one
• cleanup backend code
• the validFor setting
• autocomplete global variables instantly
• more option colors

Using validFor

Codemirror gives the option validFor, which lets you say "i found the completions for the currently typed text, and if you type one of these characters, you can just filter the results instead of asking me again". I implemented this, and now it's more snappy!

Before

https://github.com/fonsp/Pluto.jl/assets/6933510/4c39ae99-3ac5-4d80-9fbb-9be5eed5f35d

After

https://github.com/fonsp/Pluto.jl/assets/6933510/d6dbb238-e2b2-4461-a51a-f2d68ef81f39

[github-actions[bot]]

Try this Pull Request!

Open Julia and type:

  julia> import Pkg
  julia> Pkg.activate(temp=true)
  julia> Pkg.add(url="https://github.com/fonsp/Pluto.jl", rev="autocomplete-7-march-2024")
  julia> using Pluto

[fonsp]

https://github.com/JunoLab/FuzzyCompletions.jl/pull/15 would be nice!