Generate Rules.md and md###.md files from metadata, improve Parameters documentation by referencing schema.

doc/md042.md

@@ -0,0 +1,31 @@
+# MD042 - No empty links
+
+Tags: links
+
+Aliases: no-empty-links
+
+This rule is triggered when an empty link is encountered:
+
+```markdown
+[an empty link]()
+```
+
+To fix the violation, provide a destination for the link:
+
+```markdown
+[a valid link](https://example.com/)
+```
+
+Empty fragments will trigger this rule:
+
+```markdown
+[an empty fragment](#)
+```
+
+But non-empty fragments will not:
+
+```markdown
+[a valid fragment](#fragment)
+```
+
+Rationale: Empty links do not lead anywhere and therefore don't function as links.