colons vs. linking

[Dan Jacobson]

In (info "(make) Concept Index") some of these are not linked.

* -w, disabling:                         -w Option.           (line  20)
* ,v (RCS file extension):               Catalogue of Rules.  (line 162)
* :: rules (double-colon):               Double-Colon.        (line   6)
* :::=:                                  Immediate Assignment.(line   6)
* :::= <1>:                              Setting.             (line   6)
* ::=:                                   Simple Assignment.   (line   9)
* ::= <1>:                               Setting.             (line   6)
* :=:                                    Simple Assignment.   (line   9)
* := <1>:                                Setting.             (line   6)