fix: Call InputBinding.dispose() during unbinding (#2875)

InputBinding.dispose() was defined but never called. Now invoked
after unsubscribe and the shiny:unbound event in unbindInputs().
Also fixes the comment that incorrectly said "output" instead of "input".

inst/www/shared/shiny.js

@@ -1167,7 +1167,7 @@
       return;
       el;
     }
-    // This is called after unbinding the output.
+    // This is called after unbinding the input.
     dispose(el) {
       return;
       el;
@@ -5861,6 +5861,7 @@ ${duplicateIdMsg}`;
         binding,
         bindingType: "input"
       });
+      binding.dispose(el);
     }
   }
   function unbindOutputs(scope = document.documentElement, includeSelf = false) {

srcts/src/bindings/input/inputBinding.ts

@@ -87,7 +87,7 @@ class InputBinding {
     el; // eslint-disable-line @typescript-eslint/no-unused-expressions
   }
 
-  // This is called after unbinding the output.
+  // This is called after unbinding the input.
   dispose(el: HTMLElement): void {
     //empty
     return;

srcts/src/shiny/bind.ts

@@ -402,6 +402,7 @@ function unbindInputs(
       binding: binding,
       bindingType: "input",
     });
+    binding.dispose(el);
   }
 }
 function unbindOutputs(