Fix tag separator to allow hyphen separated tags like 'slow-cooked' (L…

…ukeSmithxyz#386)

Makefile

@@ -59,7 +59,7 @@ config:
 
 tags/%: $(BLOG_SRC)/%.md
 	mkdir -p tags
-	grep -ih '^; *tags:' "$<" | cut -d: -f2- | tr '[:punct:]' ' ' | sed 's/  */\n/g' | sed '/^$$/d' | sort -u > $@
+	grep -ih '^; *tags:' "$<" | cut -d: -f2- | tr -c '[^a-z\-]' ' ' | sed 's/  */\n/g' | sed '/^$$/d' | sort -u > $@
 
 blog/index.html: index.md $(ARTICLES) $(TAGFILES) $(addprefix templates/,$(addsuffix .html,header index_header tag_list_header tag_entry tag_separator tag_list_footer article_list_header article_entry article_separator article_list_footer index_footer footer))
 	mkdir -p blog