UI: Change YouTube description input to QPlainTextEdit

UI/forms/OBSYoutubeActions.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>583</width>
-    <height>452</height>
+    <height>510</height>
    </rect>
   </property>
   <property name="sizePolicy">
@@ -73,9 +73,9 @@
         </widget>
        </item>
        <item row="1" column="1">
-        <widget class="QLineEdit" name="description">
-         <property name="maxLength">
-          <number>5000</number>
+        <widget class="QPlainTextEdit" name="description">
+         <property name="tabChangesFocus">
+          <bool>true</bool>
          </property>
         </widget>
        </item>

UI/window-youtube-actions.cpp

@@ -579,7 +579,8 @@ void OBSYoutubeActions::InitBroadcast()
 void OBSYoutubeActions::UiToBroadcast(BroadcastDescription &broadcast)
 {
 	broadcast.title = ui->title->text();
-	broadcast.description = ui->description->text();
+	// ToDo: UI warning rather than silent truncation
+	broadcast.description = ui->description->toPlainText().left(5000);
 	broadcast.privacy = ui->privacyBox->currentData().toString();
 	broadcast.category.title = ui->categoryBox->currentText();
 	broadcast.category.id = ui->categoryBox->currentData().toString();