Fix Google Analytic typo (#2834)

Author: Rafnuss

R/build.R

@@ -197,14 +197,15 @@
 #'       includes:
 #'         in_header: |
 #'            <!-- Global site tag (gtag.js) - Google Analytics -->
-#'            <script async src="https://www.googletagmanager.com/gtag/js?id={YOUR TRACKING ID}"#' ></script>
+#'            <script async src="https://www.googletagmanager.com/gtag/js?id={YOUR MEASUREMENT ID}" ></script>
 #'            <script>
 #'              window.dataLayer = window.dataLayer || [];
 #'              function gtag(){dataLayer.push(arguments);}
 #'              gtag('js', new Date());
 #'
-#'              gtag('config', '{YOUR TRACKING ID}');
+#'              gtag('config', '{YOUR MEASUREMENT ID}');
 #'            </script>
+#'            <!-- Google tag (gtag.js) -->
 #'     ```
 #' *   [GoatCounter](https://www.goatcounter.com):
 #'