.github: update PULL_REQUEST_TEMPLATE to match the latest instruction

Update the wiki link too.

Change-Id: Ic3a780fa7fbdc7a7086e1a7f55932ab218d3fad9
Reviewed-on: https://go-review.googlesource.com/c/go/+/782000
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

.github/PULL_REQUEST_TEMPLATE

@@ -4,7 +4,7 @@ the Gerrit change.
 
 **Please ensure you adhere to every item in this list.**
 
-More info can be found at https://github.com/golang/go/wiki/CommitMessage
+More info can be found at https://go.dev/wiki/CommitMessage
 
 + The PR title is formatted as follows: `net/http: frob the quux before blarfing`
   + The package name goes before the colon
@@ -12,14 +12,14 @@ More info can be found at https://github.com/golang/go/wiki/CommitMessage
     "This change modifies Go to ___________"
   + Lowercase verb after the colon
   + No trailing period
-  + Keep the title as short as possible. ideally under 76 characters or shorter
+  + Keep the title as short as possible, ideally 72 characters or shorter
 + No Markdown
-+ The first PR comment (this one) is wrapped at 76 characters, unless it's
++ The first PR comment (this one) is wrapped at around 72 characters, unless it's
   really needed (ASCII art, table, or long link)
 + If there is a corresponding issue, add either `Fixes #1234` or `Updates #1234`
   (the latter if this is not a complete fix) to this comment
 + If referring to a repo other than `golang/go` you can use the
-  `owner/repo#issue_number` syntax: `Fixes golang/tools#1234`
+  `owner/repo#issue_number` syntax: `Fixes golang/vscode-go#1234`
 + We do not use Signed-off-by lines in Go. Please don't add them.
   Our Gerrit server & GitHub bots enforce CLA compliance instead.
 + Delete these instructions once you have read and applied them