- The first sentence is a summary.
- Notice the inline tag `{@link URL}`, which converts to an HTML hyperlink pointing to the documentation for the URL class.
- If you have more than one paragraph in the doc comment, separate the paragraphs with a `<p>` paragraph tag, as shown.
- Insert a blank comment line between the description and the list of tags, as shown.

	case *md.HTMLBlock:
		return strings.Join(b.Text, "\n")
	case *md.List:
		return blocksText(b.Items)
	case *md.Item:
		return blocksText(b.Blocks)
	case *md.Empty:
		return ""
	case *md.Paragraph:
		return text(b.Text)
	case *md.Quote:
		return blocksText(b.Blocks)
	case *md.ThematicBreak:
		return "---"
	default:
		panic(fmt.Sprintf("unknown block type %T", b))
	}
}

//
// Embedded struct fields are usually marshaled as if their inner exported fields
// were fields in the outer struct, subject to the usual Go visibility rules amended
// as described in the next paragraph.
// An anonymous struct field with a name given in its JSON tag is treated as
// having that name, rather than being anonymous.
// An anonymous struct field of interface type is treated the same as having

// extracts a deprecation message from that.
//
// A deprecation message is contained in a paragraph within a block of comments
// that starts with "Deprecated:" (case sensitive). The message runs until the
// end of the paragraph and does not include the "Deprecated:" prefix. If the
// comment block has multiple paragraphs that start with "Deprecated:",
// parseDeprecation returns the message from the first.

		printf.Analyzer,
	}

A driver may use the name, flags, and documentation to provide on-line
help that describes the analyses it performs.
The doc comment contains a brief one-line summary,
optionally followed by paragraphs of explanation.

The [Analyzer] type has more fields besides those shown above:

	type Analyzer struct {
		Name             string
		Doc              string
		Flags            flag.FlagSet