chore(Makefile): update golden files as part of make gen (#17039)

Updating golden files is an unnecessary extra step in addition to gen
that is easily overlooked, leading to the developer noticing the issue
in CI leading to lost developer time waiting for tests to complete.

Makefile

@@ -568,12 +568,24 @@ GEN_FILES := \
 	agent/agentcontainers/dcspec/dcspec_gen.go
 
 # all gen targets should be added here and to gen/mark-fresh
-gen: gen/db $(GEN_FILES)
+gen: gen/db gen/golden-files $(GEN_FILES)
 .PHONY: gen
 
 gen/db: $(DB_GEN_FILES)
 .PHONY: gen/db
 
+gen/golden-files: \
+	cli/testdata/.gen-golden \
+	coderd/.gen-golden \
+	coderd/notifications/.gen-golden \
+	enterprise/cli/testdata/.gen-golden \
+	enterprise/tailnet/testdata/.gen-golden \
+	helm/coder/tests/testdata/.gen-golden \
+	helm/provisioner/tests/testdata/.gen-golden \
+	provisioner/terraform/testdata/.gen-golden \
+	tailnet/testdata/.gen-golden
+.PHONY: gen/golden-files
+
 # Mark all generated files as fresh so make thinks they're up-to-date. This is
 # used during releases so we don't run generation scripts.
 gen/mark-fresh:
@@ -743,16 +755,10 @@ coderd/apidoc/swagger.json: node_modules/.installed site/node_modules/.installed
 	cd site/
 	pnpm exec biome format --write ../docs/manifest.json ../coderd/apidoc/swagger.json
 
-update-golden-files: \
-	cli/testdata/.gen-golden \
-	coderd/.gen-golden \
-	coderd/notifications/.gen-golden \
-	enterprise/cli/testdata/.gen-golden \
-	enterprise/tailnet/testdata/.gen-golden \
-	helm/coder/tests/testdata/.gen-golden \
-	helm/provisioner/tests/testdata/.gen-golden \
-	provisioner/terraform/testdata/.gen-golden \
-	tailnet/testdata/.gen-golden
+update-golden-files:
+	echo 'WARNING: This target is deprecated. Use "make gen/golden-files" instead.' 2>&1
+	echo 'Running "make gen/golden-files"' 2>&1
+	make gen/golden-files
 .PHONY: update-golden-files
 
 clean/golden-files: