Explain better what the force_valid_coordinate function does

forest/jasmine/data2mobmat.py

@@ -621,6 +621,13 @@ def gps_to_mobmat(
 
 def force_valid_longitude(longitude: float) -> float:
     """Forces a longitude coordinate to be within -180 and 180
+
+    In some cases, the imputation code seems to yield out-of-range
+    GPS coordinates. This function wrps longitude coordinates to be back
+    in the correct range so an error isn't thrown. 
+
+    For example, 190 would get transformed into -170.
+    
     Args:
         longitude: float. The longitude to be coerced
     """