Makefile: allow man-page-check to be run in parallel

This target runs several scripts in serial but they do not have any
dependencies so we can split them all into their own target so that make
-j can run the targets in parallel to speed this up.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

Makefile

@@ -590,10 +590,18 @@ podman-remote-%-docs: podman-remote
 		$(if $(findstring windows,$*),docs/source/markdown,docs/build/man)
 
 .PHONY: man-page-check
-man-page-check: bin/podman docs
+man-page-check: man-page-checker xref-helpmsgs-manpages xref-quadlet-docs xref-quadlet-docs
+
+man-page-checker: bin/podman docs
 	hack/man-page-checker
+
+xref-helpmsgs-manpages: bin/podman docs
 	hack/xref-helpmsgs-manpages
+
+man-page-table-check: docs
 	hack/man-page-table-check
+
+xref-quadlet-docs: docs
 	hack/xref-quadlet-docs
 
 .PHONY: swagger-check