Rollup merge of rust-lang#71731 - mark-i-m:guide-toolstate-off-for-now, r=kennytm

Turn off rustc-dev-guide toolstate for now

cc @rust-lang/wg-rustc-dev-guide @rust-lang/infra @ehuss

When we first added toolstate, the intent was to use toolstate to linkcheck PRs so that we would know which PRs break links in the guide (e.g. by moving some definition). However, these days, we are mostly getting 429 errors (too many requests) from github (not sure when this changed), and every day, there seems to be a spurious failure of some other sort. This is all despite efforts to filter out spurious failures.

Getting spurious gh pings is annoying, and we're not actually getting a lot out of this linkcheck beyond what we are getting with our CI on the guide's repo, so I'm proposing to disable this until we can figure out what might be a better path forward.

Author: Dylan-DPC

src/ci/docker/x86_64-gnu-tools/checktools.sh

@@ -14,7 +14,6 @@ python3 "$X_PY" test --no-fail-fast \
     src/doc/rust-by-example \
     src/doc/embedded-book \
     src/doc/edition-guide \
-    src/doc/rustc-dev-guide \
     src/tools/clippy \
     src/tools/rls \
     src/tools/rustfmt \