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

doc/md004.md

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+# MD004 - Unordered list style
+
+Tags: bullet, ul
+
+Aliases: ul-style
+
+Parameters:
+
+* `style`: List style (`string`, default `consistent`, values `asterisk`/`consistent`/`dash`/`plus`/`sublist`)
+
+Fixable: Most violations can be fixed by tooling
+
+This rule is triggered when the symbols used in the document for unordered
+list items do not match the configured unordered list style:
+
+```markdown
+* Item 1
++ Item 2
+- Item 3
+```
+
+To fix this issue, use the configured style for list items throughout the
+document:
+
+```markdown
+* Item 1
+* Item 2
+* Item 3
+```
+
+The configured list style can be a specific symbol to use (asterisk, plus, dash),
+to ensure that all list styling is consistent, or to ensure that each
+sublist has a consistent symbol that differs from its parent list.
+
+For example, the following is valid for the `sublist` style because the outer-most
+indent uses asterisk, the middle indent uses plus, and the inner-most indent uses
+dash:
+
+```markdown
+* Item 1
+  + Item 2
+    - Item 3
+  + Item 4
+* Item 4
+  + Item 5
+```
+
+Rationale: Consistent formatting makes it easier to understand a document.