Fix the Timeline Feezes.

This was caused whe TextComponent was changed from a TextEdit to a TextArea for the rich chat bar. This causes freezing for ..... reasons. Changin it back fixes the freezes.

The upshot of this is we now have to implement placeholder text ourselves. So I copied how it is done in TestArea in QQC2 desktop style with some minor logic changes for us.

src/messagecontent/TextComponent.qml

@@ -13,7 +13,7 @@ import org.kde.neochat
 /**
  * @brief A component to show rich text from a message.
  */
-QQC2.TextArea {
+TextEdit {
     id: root
 
     /**
@@ -106,15 +106,6 @@ QQC2.TextArea {
     readOnly: !root.editable
     wrapMode: Text.Wrap
     textFormat: Text.RichText
-    placeholderText: if (!editable || index !== (Message.contentModel?.hasAttachment ? 1 : 0)) {
-        return "";
-    } else if (Message.contentModel?.hasAttachment) {
-        i18nc("@placeholder", "Set an attachment caption…")
-    } else if (Message.room?.usesEncryption) {
-        i18nc("@placeholder", "Send an encrypted message…")
-    } else {
-        i18nc("@placeholder", "Send a message…")
-    }
 
     onLinkActivated: link => {
         if (!root.editable) {
@@ -129,6 +120,29 @@ QQC2.TextArea {
 
     Component.onCompleted: manageDefaultMenus()
 
+    QQC2.Label {
+        id: placeholder
+        x: root.leftPadding
+        y: root.topPadding
+        width: root.width - (root.leftPadding + root.rightPadding)
+        height: root.height - (root.topPadding + root.bottomPadding)
+
+        text: if (root.Message.contentModel?.hasAttachment) {
+            i18nc("@placeholder", "Set an attachment caption…")
+        } else if (root.Message.room?.usesEncryption) {
+            i18nc("@placeholder", "Send an encrypted message…")
+        } else {
+            i18nc("@placeholder", "Send a message…")
+        }
+        font: root.font
+        color: Kirigami.Theme.disabledTextColor
+        horizontalAlignment: root.horizontalAlignment
+        verticalAlignment: root.verticalAlignment
+        visible: root.editable && root.index === (root.Message.contentModel?.hasAttachment ? 1 : 0) && (root.Message.contentModel?.rowCount() ?? 0) <= 1 && !root.length && !root.preeditText && (!root.activeFocus || root.horizontalAlignment !== Qt.AlignHCenter)
+        elide: Text.ElideRight
+        wrapMode: Text.WordWrap
+    }
+
     HoverHandler {
         cursorShape: root.hoveredLink || (!(root.componentAttributes?.spoilerRevealed ?? false) && root.hasSpoiler) ? Qt.PointingHandCursor : Qt.IBeamCursor
     }
@@ -169,6 +183,4 @@ QQC2.TextArea {
             }
         }
     }
-
-    background: null
 }