* squashed WIP commits
* hide_gitignore working with config
* pass reference to new config parameter of file_picker()
* update config option name to match name on walk builder
* add comments to config and documentation of option to book
* add git_ignore option to WalkBuilder within prompt in commands.rs
* WIP: add FilePickerConfig struct
* WIP: cleanup
* WIP: add more options including max_depth
* WIP: changed defaults to match ignore crate defaults
* WIP: change WalkBuilder in global_search() to use config options
* WIP: removed follow_links, changed max_depth to follow config setting
* WIP: update book with file-picker inline table notation
* update documentation for file-picker config in book
* adjusted to [editor.file-picker] in book configuration.md
* adjust comments in editor.rs to be doc comments, cleanup
* adjust comments
* adjust book
* improve idle completion trigger
* add completion-trigger-len to book
* rename semantics_completion to language_server_completion and optimize idle completion trigger
Adds `ui.linenr.selected` which controls highlight of linu numbes which
have cursors on.
- Fallback to linenr if linenr.selected is missing
- Update docs and themes
- Add TODOs for themes with temporary linenr.selected