change overlooked irradiance.total_irrad references to irradiance.get_total_irradiance (#843)

Author: kandersolar

pvlib/pvsystem.py

@@ -291,7 +291,7 @@ def get_irradiance(self, solar_zenith, solar_azimuth, dni, ghi, dhi,
             Irradiance model.
 
         kwargs
-            Extra parameters passed to :func:`irradiance.total_irrad`.
+            Extra parameters passed to :func:`irradiance.get_total_irradiance`.
 
         Returns
         -------

pvlib/tracking.py

@@ -186,7 +186,7 @@ def get_irradiance(self, surface_tilt, surface_azimuth,
             Irradiance model.
 
         **kwargs
-            Passed to :func:`irradiance.total_irrad`.
+            Passed to :func:`irradiance.get_total_irradiance`.
 
         Returns
         -------