Hey everyone.

When using Emacs to compile a modern C# project, one uses the dotnet CLI to do so (dotnet build).

The output from recent dotnet CLI versions are (unfortunately) optmized for "fancyness" these days, which means it contains various escape sequences.

The current regexp in compilation-mode incorrectly includes this escape sequence for the first error reported, making navigation to the first error found fail.

Attached is a patch which excludes this escape sequence from the captured value, fixing navigation again.