Typo and translation fix

Set `...` string as notr
Capitalise `Markdown`, is a proper noun

src/widget/form/settings/avsettings.ui

@@ -77,7 +77,7 @@
           <item row="1" column="2">
            <widget class="QToolButton" name="btnPlayTestSound">
             <property name="text">
-             <string>...</string>
+             <string notr="true">...</string>
             </property>
             <property name="icon">
              <iconset resource="../../../../res.qrc">

src/widget/form/settings/generalsettings.ui

@@ -364,7 +364,7 @@ instead of closing itself.</string>
             <item>
              <widget class="QLabel" name="transLabel_2">
               <property name="toolTip">
-               <string>New markdown preference may not load until qTox restarts.</string>
+               <string>New Markdown preference may not load until qTox restarts.</string>
               </property>
               <property name="text">
                <string>Markdown:</string>