godoc/static: fix variable reference in search.txt

Change to match searchdoc.html which works.
(Was referring to "$val.Idents" in line 26, but "$val" here is
already an element of Idents.)
Also clarify naming and comments for makestatic.

Fixes golang/go#10022.

Change-Id: Ia3f2fdadd5d10f31a1825e8db966b6e92da2b93e
Reviewed-on: https://go-review.googlesource.com/6236
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
3 files changed