address requested changes

3/2 pi rad is equal to -pi/2 rad
other changes were caused by file editing issues. sorry about that.

jepler_udecimal/utrig.py

@@ -225,7 +225,7 @@ def acos(x, context=None):
     with localcontext(context) as ctx:
         ctx.prec += 2
         if x == 1:
-            r = Decimal(0). # 0 radians
+            r = Decimal(0)  # 0 radians
         elif x == -1:
             r = Decimal(1).atan() * 4  # pi radians
         else: