[3.13] Fix typos in Lib/_pydecimal.py (pythonGH-127700) (python#127887)

Fix typos in `Lib/_pydecimal.py` (pythonGH-127700)
(cherry picked from commit ed037d2)

Co-authored-by: Stan Ulbrych <[email protected]>

Author: miss-islington

Lib/_pydecimal.py

@@ -97,7 +97,7 @@ class DecimalException(ArithmeticError):
 
     Used exceptions derive from this.
     If an exception derives from another exception besides this (such as
-    Underflow (Inexact, Rounded, Subnormal) that indicates that it is only
+    Underflow (Inexact, Rounded, Subnormal)) that indicates that it is only
     called if the others are present.  This isn't actually used for
     anything, though.
 
@@ -145,7 +145,7 @@ class InvalidOperation(DecimalException):
     x ** (+-)INF
     An operand is invalid
 
-    The result of the operation after these is a quiet positive NaN,
+    The result of the operation after this is a quiet positive NaN,
     except when the cause is a signaling NaN, in which case the result is
     also a quiet NaN, but with the original sign, and an optional
     diagnostic information.