Miscellaneous iam.py docstring updates

pvlib/iam.py

@@ -270,7 +270,7 @@ def martin_ruiz(aoi, a_r=0.16):
     which is presented as :math:`AL(\alpha) = 1 - IAM` in equation 4 of [1]_,
     with :math:`\alpha` representing the angle of incidence AOI. Thus IAM = 1
     at AOI = 0, and IAM = 0 at AOI = 90.  This equation is only valid for
-    -90 <= aoi <= 90, therefore `iam` is constrained to 0.0 outside this
+    0 <= aoi <= 90, therefore `iam` is constrained to 0.0 outside this
     interval.
 
     References
@@ -891,8 +891,8 @@ def schlick_diffuse(surface_tilt):
     implements only the integrated Schlick approximation.
 
     Note also that the output of this function (which is an exact integration)
-    can be compared with the output of :py:func:`marion_diffuse` which numerically
-    integrates the Schlick approximation:
+    can be compared with the output of :py:func:`marion_diffuse` which
+    numerically integrates the Schlick approximation:
 
     .. code::