[JENKINS-43507] Documenting GitSCMBuilder

src/main/java/jenkins/plugins/git/AbstractGitSCMSource.java

@@ -617,15 +617,13 @@ protected StandardUsernameCredentials getCredentials() {
    }

    protected GitSCMBuilder newBuilder(@NonNull SCMHead head, @CheckForNull SCMRevision revision) {
        return new GitSCMBuilder(head, revision);
        return new GitSCMBuilder(head, revision, getRemote(), getCredentialsId());
    }

    @NonNull
    @Override
    public SCM build(@NonNull SCMHead head, @CheckForNull SCMRevision revision) {
        GitSCMBuilder builder = newBuilder(head, revision)
                .withRemote(getRemote())
                .withCredentials(getCredentialsId());
        GitSCMBuilder builder = newBuilder(head, revision);
        if (Util.isOverridden(AbstractGitSCMSource.class, getClass(), "getExtensions")) {
            builder.withExtensions(getExtensions());
        }
@@ -640,7 +638,7 @@ public SCM build(@NonNull SCMHead head, @CheckForNull SCMRevision revision) {
            for (RefSpec spec: getRefSpecs()) {
                specs.add(spec.toString());
            }
            builder.withRefSpecs(specs);
            builder.withoutRefSpecs().withRefSpecs(specs);
        }
        return builder.withTraits(getTraits()).build();
    }