TD: cleanup after #5457 [skip ci]

Fix header uniformity  
Fix grammar  
Fix trailing whitespace

src/Mod/TechDraw/Gui/TaskProjection.h

@@ -71,7 +71,7 @@ public:
 public:
     /// is called the TaskView when the dialog is opened
     virtual void open();
-    /// is called by the framework if an button is clicked which has no accept or reject role
+    /// is called by the framework if a button is clicked which has no accept or reject role
     virtual void clicked(int);
     /// is called by the framework if the dialog is accepted (Ok)
     virtual bool accept();