build: Enable command echo for various Makefile targets

When we run many of these together e.g. in the checks.yaml GitHub Actions
workflow, it's hard to tell from the output exactly which command is
producing which subset of the output.

To help clarify that, we'll ask make to print out the command line it's
running before it runs it.

Makefile

@@ -33,16 +33,16 @@ protobuf:
 	go run ./tools/protobuf-compile .
 
 fmtcheck:
-	@sh -c "'$(CURDIR)/scripts/gofmtcheck.sh'"
+	sh -c "'$(CURDIR)/scripts/gofmtcheck.sh'"
 
 importscheck:
-	@sh -c "'$(CURDIR)/scripts/goimportscheck.sh'"
+	sh -c "'$(CURDIR)/scripts/goimportscheck.sh'"
 
 staticcheck:
-	@sh -c "'$(CURDIR)/scripts/staticcheck.sh'"
+	sh -c "'$(CURDIR)/scripts/staticcheck.sh'"
 
 exhaustive:
-	@sh -c "'$(CURDIR)/scripts/exhaustive.sh'"
+	sh -c "'$(CURDIR)/scripts/exhaustive.sh'"
 
 # Default: run this if working on the website locally to run in watch mode.
 website: