Run toolstate jobs when src/tools/rustfmt is modified.

Previously, this would be caught by a change for modified submodules;
now that rustfmt is no longer a submodule, the check needs to be
explicit.

Author: jyn514

src/ci/scripts/should-skip-this.sh

@@ -14,10 +14,10 @@ elif git diff HEAD^ | grep --quiet "^index .* 160000"; then
     # Submodules pseudo-files inside git have the 160000 permissions, so when
     # those files are present in the diff a submodule was updated.
     echo "Executing the job since submodules are updated"
-elif git diff --name-only HEAD^ | grep --quiet src/tools/clippy; then
+elif git diff --name-only HEAD^ | grep --quiet src/tools/'\(clippy\|rustfmt\)'; then
     # There is not an easy blanket search for subtrees. For now, manually list
     # clippy.
-    echo "Executing the job since clippy subtree was updated"
+    echo "Executing the job since clippy or rustfmt subtree was updated"
 else
     echo "Not executing this job since no submodules were updated"
     ciCommandSetEnv SKIP_JOB 1