Repository: rasterio/rasterio

Issue:
Clarification on docstring for `rasterio.warp.calculate_default_transform`
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## Expected behavior and actual behavior.

The [current docstring](https://rasterio.readthedocs.io/en/latest/api/rasterio.warp.html#rasterio.warp.calculate_default_transform) for `rasterio.warp.calculate_default_transform` refers to the `width` and `height` args as output, which can direct the reader to think they refer to the destination width and height for transformation. However, `width` and `height` actually refer to the dimensions of the source dataset, and the intended dimensions are accepted as separate args `dst_width` and `dst_height`. 

Quoting relevant string below:

> Source and destination coordinate reference systems and output width and height are the first four, required, parameters.

Would like to suggest a simple reword for improved clarity: "Source and destination coordinate reference systems, and source width and height are the first four, required, parameters."

## Rasterio version and provenance

Rasterio 1.2.8



Discussion:

Resolving patch:
diff --git a/rasterio/warp.py b/rasterio/warp.py
--- a/rasterio/warp.py
+++ b/rasterio/warp.py
@@ -400,7 +400,7 @@ def calculate_default_transform(
         top=None, gcps=None, rpcs=None, resolution=None, dst_width=None, dst_height=None, **kwargs):
     """Output dimensions and transform for a reprojection.
 
-    Source and destination coordinate reference systems and output
+    Source and destination coordinate reference systems and source
     width and height are the first four, required, parameters. Source
     georeferencing can be specified using either ground control points
     (gcps) or spatial bounds (left, bottom, right, top). These two


Test patch: