fix: formatting of plot-title in placeholder

Added missing music_discs from 1.21.6 & 1.21.7

Core/src/main/java/com/plotsquared/core/command/Music.java

@@ -57,7 +57,7 @@ public class Music extends SubCommand {
                     "music_disc_far", "music_disc_mall", "music_disc_mellohi", "music_disc_stal",
                     "music_disc_strad", "music_disc_ward", "music_disc_11", "music_disc_wait", "music_disc_otherside",
                     "music_disc_pigstep", "music_disc_5", "music_disc_relic", "music_disc_creator",
-                    "music_disc_creator_music_box", "music_disc_precipice"
+                    "music_disc_creator_music_box", "music_disc_precipice", "music_disc_tears", "music_disc_lava_chicken"
             );
 
     // make sure all discs and the bedrock ("cancel") fit into the inventory

Core/src/main/java/com/plotsquared/core/plot/PlotTitle.java

@@ -63,4 +63,18 @@ public class PlotTitle {
         return subtitle;
     }
 
+    /**
+     * Provides a string representation of this plot title value (used in placeholders).
+     *
+     * @return the plot title representation in the format {@code "<title>" "<subtitle>"}
+     * @since TODO
+     */
+    @Override
+    public String toString() {
+        return "\"%s\" \"%s\"".formatted(
+                this.title != null ? this.title : "",
+                this.subtitle != null ? this.subtitle : ""
+        );
+    }
+
 }