Update Roslyn Insertion Tool docs

The https://github.com/dotnet/roslyn-tools/blob/main/src/RoslynInsertionTool/README.md is severely in need of an update.

Some options no longer exist and several other new ones aren't there. Perhaps it would also be a good time to use the full names instead of abbreviations as things like `bn`, `ac`, and `qv` are not intuitive.

Start with src/RoslynInsertionTool/README.md and compare its documented options with the current Roslyn Insertion Tool. Identify options that no longer exist, add the missing options, and replace unclear abbreviations such as bn, ac, and qv with full names; the README should accurately describe the current tool.

Written by the indexing model from the issue text.