minor wording tweak and fix import in python unit test_agg_local_mean

Signed-off-by: Jason T. Brown <[email protected]>

Author: vpipkt

pyrasterframes/src/main/python/docs/getting-started.pymd

@@ -115,4 +115,4 @@ from pyrasterframes.utils import gdal_version
 print(gdal_version())
 ```
 
-This will print out somethin like "GDAL x.y.z, released 20yy/mm/dd". If it reports `unavailable`, then GDAL isn't installed in a place where the RasterFrames runtime was able to find it. Please [file an issue](https://github.com/locationtech/rasterframes/issues) to get help resolving it.
+This will print out something like "GDAL x.y.z, released 20yy/mm/dd". If it reports `not available`, then GDAL isn't installed in a place where the RasterFrames runtime was able to find it. Please [file an issue](https://github.com/locationtech/rasterframes/issues) to get help resolving it.

pyrasterframes/src/main/python/tests/RasterFunctionsTests.py

@@ -98,6 +98,8 @@ def test_agg_mean(self):
 
     def test_agg_local_mean(self):
         from pyspark.sql import Row
+        from pyrasterframes.rf_types import Tile
+        import numpy as np
 
         # this is really testing the nodata propagation in the agg  local summation
         ct = CellType.int8().with_no_data_value(4)