Fix some trivial problems (#36336)

1. correctly parse git protocol's "OldCommit NewCommit RefName" line, it
should be explicitly split by space
2. add missing "return" in CreatePullRequest
3. add comments for "/user.keys" and "/user.gpg" outputs
4. trim space for the "commit status context name" to follow the same
behavior of git_model.NewCommitStatus

routers/api/v1/repo/pull.go

@@ -500,6 +500,7 @@ func CreatePullRequest(ctx *context.APIContext) {
 	unitPullRequest, err := ctx.Repo.Repository.GetUnit(ctx, unit.TypePullRequests)
 	if err != nil {
 		ctx.APIErrorInternal(err)
+		return
 	}
 
 	prIssue := &issues_model.Issue{

routers/web/user/home.go

@@ -660,6 +660,8 @@ func ShowSSHKeys(ctx *context.Context) {
 	}
 
 	var buf bytes.Buffer
+	// "authorized_keys" file format: "#" followed by comment line per key
+	buf.WriteString("# Gitea isn't a key server. The keys are exported as the user uploaded and might not have been fully verified.\n")
 	for i := range keys {
 		buf.WriteString(keys[i].OmitEmail())
 		buf.WriteString("\n")
@@ -695,6 +697,8 @@ func ShowGPGKeys(ctx *context.Context) {
 	var buf bytes.Buffer
 
 	headers := make(map[string]string)
+	// https://www.rfc-editor.org/rfc/rfc4880
+	headers["Comment"] = "Gitea isn't a key server. The keys are exported as the user uploaded and might not have been fully verified."
 	if len(failedEntitiesID) > 0 { // If some key need re-import to be exported
 		headers["Note"] = "The keys with the following IDs couldn't be exported and need to be reuploaded " + strings.Join(failedEntitiesID, ", ")
 	} else if len(entities) == 0 {