chore(tvix/eval): add dependency on codemap-diagnostic

This is a crate for source-span based error reporting. Since all of
our spans are already codemap spans, it is a good starting point.

We have to figure out quite a bit of logic for neat error printing;
later on if we want fancier presentation we might want to look at one
of the other libraries in this space like miette.

Change-Id: I4e28886af1ed199b7112d9dbf063c9f29b612bf1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6531
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: grfn <grfn@gws.fyi>

tvix/eval/Cargo.toml

@@ -20,6 +20,7 @@ path-clean = "0.1"
 tabwriter = "1.2"
 rowan = "*" # pinned by rnix
 codemap = "0.1.3"
+codemap-diagnostic = "0.1.1"
 
 # rnix has not been released in a while (as of 2022-09-01), we will
 # use it from git.