* dynamically resize line number gutter width
* removing digits lower-bound, permitting spacer
* removing max line num char limit; adding notes; qualified successors; notes
* updating tests to use new line number width when testing views
* linenr width based on document line count
* using min width of 2 so line numbers relative is useful
* lint rolling; removing unnecessary type parameter lifetime
* merge change resolution
* reformat code
* rename row_styler to style; add int_log resource
* adding spacer to gutters default; updating book config entry
* adding view.inner_height(), swap for loop for iterator
* reverting change of current! to view! now that doc is not needed
Underline styles are mutally exclusive and overwrite each other.
Therefore implementing as an modifier lead to incorrect behaviour
when the underline style is overwritten.
For backwards compatability the "underline" modified is retained (but
deprecated). Instead the "underline_style" and "underline_color"
optios should be used to style underlines.
* Display highest severity diagnostic in gutter
* Improve gutter diagnostic performance
Very slight improvement (doesn't really make a difference), iterates over the diagnostics of the line
once instead of twice.
* Add comment justifying unwrap
