internal/task: remove repetition in major Go release tweets

There was accidentally one too many "go" in the tweet text
for the major Go release type.

Updates golang/go#47403.
Updates golang/go#40279.

Change-Id: I7983bdb78f22c258121348a6cfaa2ed66592db54
Reviewed-on: https://go-review.googlesource.com/c/build/+/393018
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>

internal/task/tweet.go

@@ -217,7 +217,13 @@ func tweetText(r ReleaseTweet, rnd *rand.Rand) (string, error) {
 			ReleaseTweet: r,
 		}
 	} else if strings.Count(r.Version, ".") == 1 { // Major release like "go1.X".
-		name, data = "major", r
+		name, data = "major", struct {
+			Maj string
+			ReleaseTweet
+		}{
+			Maj:          r.Version[len("go"):],
+			ReleaseTweet: r,
+		}
 	} else if strings.Count(r.Version, ".") == 2 { // Minor release like "go1.X.Y".
 		name, data = "minor", struct {
 			Curr, Prev string
@@ -279,7 +285,7 @@ const tweetTextTmpl = `{{define "minor" -}}
 
 
 {{define "major" -}}
-{{emoji "release"}} Go {{.Version}} is released!
+{{emoji "release"}} Go {{.Maj}} is released!
 
 {{with .Security}}{{emoji "security"}} Security: {{.}}{{"\n\n"}}{{end -}}
 

internal/task/tweet_test.go

@@ -128,7 +128,7 @@ go version go1.17rc2 windows/arm64` + "\n",
 				RandomSeed: 123,
 			},
 			wantLog: `tweet text:
-🥳 Go go1.17 is released!
+🥳 Go 1.17 is released!
 
 🔐 Security: Includes a super duper security fix (CVE-123).