Update resume_from_checkpoint docs (#9952)

Author: carmocca

pytorch_lightning/trainer/connectors/checkpoint_connector.py

@@ -59,9 +59,6 @@ def resume_start(self) -> None:
         1. from HPC weights if found
         2. from `resume_from_checkpoint` file if provided
         3. don't restore
-
-        Raises:
-            FileNotFoundError: If the path to the checkpoint file is provided but the file does not exist.
         """
         self.resume_checkpoint_path = self.hpc_resume_path or self.resume_checkpoint_path
         checkpoint_path = self.resume_checkpoint_path

pytorch_lightning/trainer/trainer.py

@@ -357,7 +357,7 @@ def __init__(
                 you can set ``replace_sampler_ddp=False`` and add your own distributed sampler.
 
             resume_from_checkpoint: Path/URL of the checkpoint from which training is resumed. If there is
-                no checkpoint file at the path, start from scratch. If resuming from mid-epoch checkpoint,
+                no checkpoint file at the path, an exception is raised. If resuming from mid-epoch checkpoint,
                 training will start from the beginning of the next epoch.
 
             strategy: Supports different training strategies with aliases