add missing point for install instruction

Author: liufengyun

docs/_includes/getting-started.html

@@ -10,7 +10,7 @@ <h1 id="getting-started">Try Dotty</h1>
         <p>Now you can compile Scala source code:<p>
         <pre class="sourceCode bright"><code>dotc hello.scala</code></pre>
 
-        <p>To start the RPEL, run: <code>dotr</code><p>
+        <p>To start the RPEL, run: <code>dotr</code>.<p>
 
         <p>Or, you can try Dotty in your browser with <a href="https://scastie.scala-lang.org/?target=dotty">Scastie</a>.</p>