Revert "content: update text in fetch.tmpl for 404s"
Revert "content: update text in fetch.tmpl for 404s"

This reverts commit 369bd985a39adb1aa39cbd165f4fb4cd6d7224f6.

Reason for revert: I forgot I marked CL 245646 as WIP because
I had to fix a test.

Change-Id: Ic2f7edf97733630f39d8a730829abcd2a306a0e6
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/245879
Reviewed-by: Jamal Carvalho <e0195770807aa8c82b0b128d9c0423b5ad035172@golang.org>

golang/pkgsite,golang/pkgsite,golang/pkgsite,golang/pkgsite