Changes are mostly about making more about now than about the past,
changing some verb tenses, and mentioning gollvm (which should
be pronounced "gollum" if you ask me).

Update #26107

Change-Id: I6c14f42b9fc2684259d4ba8bc149d7ec9bb83d15
Reviewed-on: https://go-review.googlesource.com/123917Reviewed-by: Ian Lance Taylor <iant@golang.org>