Running the spacetime publish command in the absence of a Cargo.toml or a C# project gives a cryptic error message about dotnet

[cloutiertyler]

This is a well known issue, but the essence of it is, we use the presence of a Cargo.toml file to determine if we should run C# related commands.

~/clockwork/blackholio
$ spacetime publish --server local blackholio
MSBUILD : error MSB1003: Specify a project or solution file. The current working directory does not contain a project or solution file.
Error: command ["dotnet", "publish", "-c", "Release", "-v", "quiet"] exited with code 1

At the very least the DoD for this ticket is that if you run outside of a directory which could potentially be compiled into either a C# module or a Rust module, that you get an error that is more like:

No spacetime module in directory: /foo/bar
Did you mean to run publish on a different directory?