Fix Makefile incorrect peer target usage (#608)

Author: straight-shoota

docs.mk

@@ -20,7 +20,10 @@ manpages: $(MAN_FILES)
 htmlpages: ## Generate HTML files from adoc
 htmlpages: $(HTML_FILES)
 
-man/%.1 man/%.5: docs/%.adoc
+man/%.1: docs/%.adoc
+	SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH) $(ASCIIDOC) $(ASCIIDOC_OPTIONS) $< -b manpage -o $@
+
+man/%.5: docs/%.adoc
 	SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH) $(ASCIIDOC) $(ASCIIDOC_OPTIONS) $< -b manpage -o $@
 
 docs/%.html: docs/%.adoc