Add GCCRS support in the Rust config (#2628)
Add GCCRS support in the Rust config (#2628)

Add gccrs-snapshot config pointing to the daily build.
dkm/gcc-explorer,mattgodbolt/compiler-explorer,mattgodbolt/compiler-explorer,mattgodbolt/compiler-explorer,mattgodbolt/gcc-explorer,dkm/gcc-explorer,mattgodbolt/compiler-explorer,mattgodbolt/compiler-explorer,mattgodbolt/gcc-explorer,mattgodbolt/compiler-explorer,mattgodbolt/compiler-explorer,mattgodbolt/compiler-explorer,dkm/gcc-explorer,dkm/gcc-explorer,mattgodbolt/gcc-explorer,dkm/gcc-explorer,dkm/gcc-explorer,mattgodbolt/gcc-explorer,dkm/gcc-explorer,dkm/gcc-explorer,dkm/gcc-explorer,mattgodbolt/gcc-explorer