- Fix an off-by-one error when a fix-it continues onto a newline
- Don't print multi-line insertions inline due to poor UX
- When printing multi-line fix-its out of line attached to a message,
replace newlines with the carriage return emoji
- Don't underline a line's leading whitespace unless it's part of an insertion
* [Diagnostics] Experimental diagnostic printing updates
This new style directly annotates small snippets of code with
error messages, highlights and fix-its. It also uses color more
effectively to highlight important segments.
* [Diagnostics] Stage educational notes and experimental formatting behind separate frontend flags
educational notes -> -enable-educational-notes
formatting -> -enable-experimental-diagnostic-formatting
* [Diagnostics] Refactor expensive line lookups in diag formatting
* [Diagnostics] Refactor some PrintingDiagnosticConsumer code into a flush method
* [Diag-Experimental-Formatting] Custom formatting for Xcode editor placeholders
* [Diag-Experimental-Formatting] Better and more consistent textual description of fix its
* [Diags-Experimental-Formatting] Handle lines with tab characters correctly when rendering highlights and messages
Tabs are converted to 2 spaces for display purposes.
* [Diag-Experimental-Formatting] Refactor byte-to-column mapping for efficiency
* [Diag-Experimental-Formatting] Fix line number indent calculation
* [Diag-Experimental-Formatting] Include indicators of insertions and deletions in the highlight line
Inserts are underlined by green '+' chars, deletions by red '-' chars.
* [Diag-Experimental-Formatting] Change color of indicator arrow for non-ASCII anchored messages
* [Diag-experimental-formatting] Make tests less sensitive to line numbering
* [Diag-Experimental-Formatting] Update tests to allow windows path separators
* [Diag-Experimental-Formatting] Bug fixes for the integrated REPL
