Fix plantuml mode title

Yukaii · Yukaii · commit 8ecfc73a9bec · 2020-07-30T11:32:34.000+08:00
diff --git a/mode/plantuml/index.html b/mode/plantuml/index.html
@@ -1,5 +1,5 @@
 <!doctype html>
-<title>CodeMirror: Pig Latin mode</title>
+<title>CodeMirror: PlantUML mode</title>
 <meta charset="utf-8"/>
 <link rel=stylesheet href="../../doc/docs.css">
 
