Improve Editor Configuration, Rename to SourceEditor

[thecoolwinter]

Description

Improved the organization of our editor's configuration options by organizing them into a separate type from the SwiftUI API. This type is further organized into four structs based on the configuration option's effect on the editor.

Detailed Changes

• Creates a new SourceEditorConfiguration struct.
  • Passed to CodeEditSourceEditor and TextViewController to update configuration.
  • One single object for all configuration that doesn't usually change during editing (no state is stored here).
  • Has an efficient method for updating the editor for a new configuration (moved from CodeEditSourceEditor's SwiftUI update method to SourceEditorConfiguration).
  • Organized into four categories: appearance, behavior, layout, and peripherals. Each has it's own documentation.
• Adds a new API for toggling the gutter view.
• Renames CodeEditSourceEditor to SourceEditor (requested by @austincondiff).
• Updates docc docs to reflect new API.
• Updates README to reflect new API (as well as a few missing/broken links).

I found a small bug with the refactor guide while making these changes. I may move them out of this PR.

Related Issues

• closes ✨ Configuration to toggle line numbers visibility #115
• closes ✨ Config Getting Large #319

Checklist

• I read and understood the contributing guide as well as the code of conduct
• The issues this PR addresses are related to each other
• My changes generate no new warnings
• My code builds and runs on my machine
• My changes are all related to the related issue above
• I documented my code

Screenshots

N/A no content changes

[0xWDG]

🚀