Further wording improvements.

doc/go1.16.html

@@ -91,7 +91,7 @@ Do not send CLs removing the interior tags from such phrases.
   fetching from repositories and resolving custom domains using insecure
   schemes such as HTTP, and also bypassess module sum validation using the
   checksum database. To permit the use of insecure schemes, use the
-  <code>GOINSECURE</code> environment variable instead. To disable module
+  <code>GOINSECURE</code> environment variable instead. To bypass module
   sum validation, use <code>GOPRIVATE</code> or <code>GONOSUMDB</code>.
   See <code>go</code> <code>help</code> <code>environment</code> for details.
 </p>

src/cmd/go/alldocs.go

@@ -666,7 +666,7 @@
 // module sum validation using the checksum database. Use with caution.
 // This flag is deprecated and will be removed in a future version of go.
 // To permit the use of insecure schemes, use the GOINSECURE environment
-// variable instead. To disable module sum validation, use GOPRIVATE or
+// variable instead. To bypass module sum validation, use GOPRIVATE or
 // GONOSUMDB. See 'go help environment' for details.
 //
 // The second step is to download (if needed), build, and install

src/cmd/go/internal/modget/get.go

@@ -119,7 +119,7 @@ custom domains using insecure schemes such as HTTP, and also bypassess
 module sum validation using the checksum database. Use with caution.
 This flag is deprecated and will be removed in a future version of go.
 To permit the use of insecure schemes, use the GOINSECURE environment
-variable instead. To disable module sum validation, use GOPRIVATE or
+variable instead. To bypass module sum validation, use GOPRIVATE or
 GONOSUMDB. See 'go help environment' for details.
 
 The second step is to download (if needed), build, and install