make: Add missing dependency between schemas and schema bundle

Reported-by: microsatoshi

Makefile

@@ -588,8 +588,8 @@ CHECK_GEN_ALL = \
 	$(PYTHON_GENERATED) \
 	$(ALL_GEN_HEADERS) \
 	$(ALL_GEN_SOURCES) \
+	$(MSGGEN_GEN_ALL) \
 	wallet/statements_gettextgen.po \
-	.msggen.json \
 	doc/index.rst
 
 gen:  $(CHECK_GEN_ALL)
@@ -706,6 +706,7 @@ clean: obsclean
 	$(RM) $(ALL_PROGRAMS)
 	$(RM) $(ALL_TEST_PROGRAMS)
 	$(RM) $(ALL_FUZZ_TARGETS)
+	$(RM) $(MSGGEN_GEN_ALL)
 	$(RM) ccan/tools/configurator/configurator
 	$(RM) ccan/ccan/cdump/tools/cdump-enumstr.o
 	find . -name '*gcda' -delete

contrib/msggen/Makefile

@@ -1,4 +1,15 @@
 #! /usr/bin/make
 
+# Files that `msggen` generates for itself, this does not include the
+# artifacts that we will be using `msggen` to generate, but rather all
+# the files required to work itself. This is distinct from
+# `MSGGEN_GENALL`, which consists only of the files generated using
+# `msggen`. `msggen.json` is special, it contains information that must not change, therefore it is not included in `clean` calls.
+MSGGEN_GEN_ALL = \
+	contrib/msggen/msggen/schema.json
+
+MSGGEN_DATA = \
+	.msggen.json
+
 contrib/msggen/msggen/schema.json: ${SCHEMAS}
 	PYTHONPATH=contrib/msggen ${PYTHON} contrib/msggen/msggen/__main__.py bundle doc/schemas