Repository: Lightning-AI/pytorch-lightning
Pull request: docs: default_root_path -> default_root_dir
## What does this PR do?

Remove occurrences of default_root_path: the argument is default_root_dir for `Trainer`.

Fixes #4926 

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Problem statement:
default_root_path vs default_root_dir
I noticed that the argument to Trainer is `default_root_dir`, but the docs sometimes show `default_root_path`. I did a grep on the codebase for `default_root_path`, and here are the results:

```
./notebooks/05-trainer-flags-overview.ipynb:2155:    "trainer = pl.Trainer(default_root_path=os.getcwd())\n",
./pytorch_lightning/trainer/properties.py:51:    default_root_path: str
./docs/source/trainer.rst:618:    trainer = Trainer(default_root_path=os.getcwd())
```

I'm fairly convinced it's simply a documentation issue, but it requires some code changes (the 2nd line), and I'm not sure whether that will affect anything.

Hints from issue discussion:
Hi! thanks for your contribution!, great first issue!
It should be fine. Can you open a PR?

Commit message: Apply suggestions from code review

Patch to review:
diff --git a/docs/source/trainer.rst b/docs/source/trainer.rst
index c390db8d7537e..55914eb686539 100644
--- a/docs/source/trainer.rst
+++ b/docs/source/trainer.rst
@@ -612,10 +612,10 @@ stored. If you don't then use this argument for convenience. Paths can be local
 paths or remote paths such as `s3://bucket/path` or 'hdfs://path/'. Credentials
 will need to be set up to use remote filepaths.
 
-Example::
+.. testcode::
 
     # default used by the Trainer
-    trainer = Trainer(default_root_path=os.getcwd())
+    trainer = Trainer(default_root_dir=os.getcwd())
 
 distributed_backend
 ^^^^^^^^^^^^^^^^^^^
diff --git a/pytorch_lightning/trainer/properties.py b/pytorch_lightning/trainer/properties.py
index 09022d5b37094..54b692d26ccec 100644
--- a/pytorch_lightning/trainer/properties.py
+++ b/pytorch_lightning/trainer/properties.py
@@ -48,7 +48,7 @@ class TrainerProperties(ABC):
     limit_val_batches: int
     _default_root_dir: str
     _weights_save_path: str
-    default_root_path: str
+    default_root_dir: str
     accelerator_backend: Accelerator
     logger: LightningLoggerBase
     model_connector: ModelConnector


Code review comments:
diff_hunk: @@ -48,7 +48,7 @@ class TrainerProperties(ABC):
     limit_val_batches: int
     _default_root_dir: str
     _weights_save_path: str
-    default_root_path: str
+    default_root_dir: str
path: pytorch_lightning/trainer/properties.py
text: @user1:
I think this should be removed instead, we already have `_default_root_dir`
```suggestion
```