Don't try to shellcheck src/rust/registry

Fixes bug 30963; bug not in any released Tor.

Makefile.am

@@ -224,7 +224,7 @@ test: all
 shellcheck:
         # Only use shellcheck if it is present
 	if command -v shellcheck; then \
-                find "$(top_srcdir)" -name "*.sh" -not -path "$(top_srcdir)/src/ext/*" -exec shellcheck {} +; \
+                find "$(top_srcdir)" -name "*.sh" -not -path "$(top_srcdir)/src/ext/*" -not -path "$(top_srcdir)/src/rust/registry/*" -exec shellcheck {} +; \
 	        if [ -d "$(top_srcdir)/scripts/test" ]; then \
                         shellcheck $(top_srcdir)/scripts/test/cov-diff $(top_srcdir)/scripts/test/coverage; \
                 fi; \