internal/goversion: update Version to 1.16

This is the start of the Go 1.16 development cycle, so update the
Version value accordingly. It represents the Go 1.x version that
will soon open up for development (and eventually become released).

Historically, we used to bump this at an arbitrary time throughout
the development cycle, but it's better to be more predictable about
updating it. The start of a development cycle should be the most
appropriate time: it clearly marks the boundary between 1.15 and
1.16 development, and doing it early can help catch issues in other
tooling. See issue #38704 for more background.

There is no longer a need to update the list of Go versions in
src/go/build/doc.go because it does not exist as of CL 232981.

For #40705.
Updates #38704.
Updates #37018.

Change-Id: Id8ee733b5e79c53b6cd03509c6560614d8743833
Reviewed-on: https://go-review.googlesource.com/c/go/+/248038
Reviewed-by: Carlos Amedee <[email protected]>

Author: dmitshur

src/internal/goversion/goversion.go

@@ -4,10 +4,9 @@
 
 package goversion
 
-// Version is the current Go 1.x version. During development cycles on
-// the master branch it changes to be the version of the next Go 1.x
-// release.
+// Version is the Go 1.x version which is currently
+// in development and will eventually get released.
 //
-// When incrementing this, also add to the list at src/go/build/doc.go
-// (search for "onward").
-const Version = 15
+// It should be updated at the start of each development cycle to be
+// the version of the next Go 1.x release. See golang.org/issue/40705.
+const Version = 16