man.cgi overzealosly hyperlinking

[Alexey Dobriyan <adobriyan_(_at_)_gmail_(_dot_)_com>]

Steps to reproduce:

	fire up web interface to man pages
	go to fgetln(3)
	scroll down to an example
	notice that "free(lbuf)" is hyperlinked

Of course, there is no section "lbuf". Ditto for

* "0 (NULL)" in intro(2)
* "ffs (local)" in afterboot(8)

The first bug is attributed to two letters in section regexp.

man.cgi:
   476		/^\s/ && 			# skip headers
   477		    s,((<[IB]>)?[\w\_\.\-]+\s*(</[IB]>)?\s*\(([1-9ln][a-zA-Z]*)\)),&mlnk($1),oige;
							          ^^

4/* sections don't work as well. See "EBus (4/SPARC64)" on 4-catch-all
page.