Update pvlib/bifacial/utils.py

Co-authored-by: Adam R. Jensen <39184289+AdamRJensen@users.noreply.github.com>

Author: kandersolar

pvlib/bifacial/utils.py

@@ -442,8 +442,8 @@ def vf_row_sky_2d_integ(surface_tilt, gcr, x0=0, x1=1):
         Ratio of the row slant length to the row spacing (pitch). [unitless]
     x0 : numeric, default 0
         Position on the row's slant length, as a fraction of the slant length.
-        ``x0=0`` corresponds to the bottom of the row. ``x0`` should be less
-        than ``x1``. [unitless]
+        ``x0=0`` corresponds to the lower edge of the row. ``x0`` should
+        be less than ``x1``. [unitless]
     x1 : numeric, default 1
         Position on the row's slant length, as a fraction of the slant length.
         ``x1`` should be greater than ``x0``. [unitless]