QtFRED Waypoint Dialog Upgrade (scp-fs2open#7419)

* make waypoint multi select and direct edit

* clang

* update qtfred help docs

* fixes

* static

* address feedback

Author: MjnMixael

qtfred/help-src/doc/dialogs/WaypointEditorDialog.html

@@ -14,20 +14,32 @@ <h1>Waypoint Editor</h1>
 Waypoint paths are simply ordered sequences of arbitrary positions in space and can
 be used for any purpose a mission designer can express through SEXPs and AI goals.</p>
 
+<p>The dialog tracks the viewport selection. Select waypoint objects in the viewport
+to edit their path. When multiple paths are selected, display property changes
+(No Draw Lines, Custom Color, Layer) apply to all selected paths at once.</p>
+
+<h2>Navigation</h2>
+<table>
+    <tr><th>Button</th><th>Description</th></tr>
+    <tr><td>Prev / Next</td><td>Cycles the viewport selection to the previous or next
+        waypoint path in the mission, allowing sequential editing without switching
+        back to the viewport.</td></tr>
+</table>
+
 <h2>Key fields</h2>
 <table>
     <tr><th>Field</th><th>Description</th></tr>
-    <tr><td>Waypoint path</td><td>Selects which path to edit. New paths are created by
-        placing waypoint objects in the viewport.</td></tr>
     <tr><td>Name</td><td>Identifies the path in SEXPs and AI goal assignments. Must be
-        unique.</td></tr>
-    <tr><td>Layer</td><td>The layer the waypoint path is assigned to.</td></tr>
+        unique. When multiple paths are selected the Name field is read-only. Rename
+        single paths individually.</td></tr>
+    <tr><td>Layer</td><td>The layer the waypoint path is assigned to. Applied to all
+        selected paths.</td></tr>
     <tr><td>No Draw Lines</td><td>When checked, the connecting lines between waypoints
         are hidden in the viewport. The waypoint points themselves are still
-        visible.</td></tr>
+        visible. Applied to all selected paths.</td></tr>
     <tr><td>Custom Color</td><td>When checked, enables the RGB fields below to set a
         custom color for rendering this path's points and lines in the viewport.
-        Does not affect in-game appearance.</td></tr>
+        Does not affect in-game appearance. Applied to all selected paths.</td></tr>
 </table>
 
 <div class="note">Individual waypoint positions are moved by selecting the waypoint