docs(source_utils): improve docstring for InputSource type

- Clarified the description of the `InputSource` type to specify that it includes both images and files for `askui.VisionAgent.get()` and images for `askui.VisionAgent.locate()`.

Author: danyalxahid-askui

src/askui/utils/source_utils.py

@@ -15,8 +15,8 @@
 
 InputSource = Union[str, Path, PILImage.Image]
 """
-Type of the input images for `askui.VisionAgent.get()`, `askui.VisionAgent.locate()`,
-etc.
+Type of the input images and files for `askui.VisionAgent.get()` and images for 
+`askui.VisionAgent.locate()`, etc.
 
 Accepts:
 - `PIL.Image.Image`