gh-110704: Recommend distclean target over clean when source tree is not clean (GH-112610)

Recommend `distclean` target over `clean` when source tree is not clean

Co-authored-by: Gregory P. Smith <greg@krypto.org>

Author: SnoopJ

Makefile.pre.in

@@ -795,7 +795,7 @@ check-clean-src:
 		echo "Building Python out of the source tree (in $(abs_builddir)) requires a clean source tree ($(abs_srcdir))" ; \
 		echo "Build artifacts such as .o files, executables, and Python/frozen_modules/*.h must not exist within $(srcdir)." ; \
 		echo "Try to run:" ; \
-		echo "  (cd \"$(srcdir)\" && make clean || git clean -fdx -e Doc/venv)" ; \
+		echo "  (cd \"$(srcdir)\" && make distclean || git clean -fdx -e Doc/venv)" ; \
 		exit 1; \
 	fi