<li>Each <a href="#Packages">package</a> has a <i>package block</i> containing all
	    Go source text for that package.</li>

	<li>Each file has a <i>file block</i> containing all Go source text
	    in that file.</li>

	<li>Each <a href="#If_statements">"if"</a>,
	    <a href="#For_statements">"for"</a>, and
	    <a href="#Switch_statements">"switch"</a>

pkg io/fs, type DirEntry interface, Type() FileMode
pkg io/fs, type FS interface { Open }
pkg io/fs, type FS interface, Open(string) (File, error)
pkg io/fs, type File interface { Close, Read, Stat }
pkg io/fs, type File interface, Close() error
pkg io/fs, type File interface, Read([]uint8) (int, error)
pkg io/fs, type File interface, Stat() (FileInfo, error)
pkg io/fs, type FileInfo interface { IsDir, ModTime, Mode, Name, Size, Sys }