replace tui-textarea with a custom textarea / fork

[achristmascarl]

description

currently, rainfrog uses tui-textarea for the query editor. it's a great library with a lot of features, however, there are a few limitations:

• syntax highlighting is currently not supported, so we use a hacky regex and the tui-textarea's search feature to do it. this is not very performant and also is not a great experience
• some internal offsets are not currently exposed, making it hard to do things like auto-completion overlays / popups
• the cursor's end-of-line behavior and insert-mode behavior is different from vim's, making some elements of vim emulation tricky

proposed solution

check out https://docs.rs/rat-widget/latest/rat_widget/textarea/struct.TextArea.html as a potential replacement. however, the library (rat-widget) is still in alpha and doesn't have much of a test suite, so although it has more flexibility, it may not be as reliable yet.

or, stick with tui-textarea, and instead of incrementally requesting desired features in tui-textarea, either make a fork and implement:

• syntax highlighting (PoC accomplished in a fork already: Feature Request: syntax highlighting rhysd/tui-textarea#63)
• auto-completion
• better vim emulation
  ... and use the fork instead.

or, wait for rhysd/tui-textarea#82 to be resolved, and layer in inlays/overlays/syntax highlighting on top of tui-textarea. i think it's possible, but the syntax highlighting implementation might be a little hacky