Improve how cached wheels are presented

This is specifically for the case of look ups done in the new resolver.

src/pip/_internal/operations/prepare.py

@@ -374,7 +374,7 @@ def _download_should_save(self):
     def _log_preparing_link(self, req):
         # type: (InstallRequirement) -> None
         """Provide context for the requirement being prepared."""
-        if req.link.is_file:
+        if req.link.is_file and not req.original_link_is_in_wheel_cache:
             message = "Processing %s"
             information = str(display_path(req.link.file_path))
         else:
@@ -383,6 +383,10 @@ def _log_preparing_link(self, req):
 
         logger.info(message, information)
 
+        if req.original_link_is_in_wheel_cache:
+            with indent_log():
+                logger.info("Using cached %s", req.link.filename)
+
     def _get_download_dir(self, link):
         # type: (Link) -> Optional[str]
         if link.is_wheel and self.wheel_download_dir: