Add support for sorting more keywords and nested types

[craigktreasure]

• Added support for sorting members with the readonly keyword and nested types.
• Added more details to the exception that is thrown while trying to sort by name to make it easier to debug in the future.
• Fixed a bug in the logic used to maintain whitespace when reordering that was causing comments to get swapped.

[codecov]

Codecov Report

Merging #10 (02104e4) into main (ce4f97d) will increase coverage by 2.04%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##             main       #10      +/-   ##
===========================================
+ Coverage   97.95%   100.00%   +2.04%     
===========================================
  Files           2         3       +1     
  Lines          98       113      +15     
===========================================
+ Hits           96       113      +17     
+ Misses          2         0       -2     

Files	Coverage Δ
...emberOrder.CodeFixes/MemberOrderCodeFixProvider.cs	100.00% <100.00%> (ø)
...berOrder/MemberOrder.CodeFixes/SyntaxExtensions.cs	100.00% <100.00%> (ø)
src/MemberOrder/MemberOrder/MemberOrderAnalyzer.cs	100.00% <100.00%> (+2.43%)	⬆️

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[craigktreasure]

Fixed #8 and #9.