fix --source-entity option passed to Haddock: we needed to escape a #

rules/haddock.mk

@@ -34,7 +34,7 @@ html_$1 : $$($$($1_PACKAGE)-$$($1_$2_VERSION)_HADDOCK_FILE)
 $$($1_PACKAGE)-$$($1_$2_VERSION)_HADDOCK_DEPS = $$(foreach n,$$($1_$2_DEPS),$$($$n_HADDOCK_FILE) $$($$n_dist-install_v_LIB))
 
 ifeq "$$(HSCOLOUR_SRCS)" "YES"
-$1_$2_HADDOCK_FLAGS += --source-module=src/%{MODULE/./-}.html --source-entity=src/%{MODULE/./-}.html#%{NAME}
+$1_$2_HADDOCK_FLAGS += --source-module=src/%{MODULE/./-}.html --source-entity=src/%{MODULE/./-}.html\#%{NAME}
 endif
 
 ifneq "$$(BINDIST)" "YES"