Fix pickletools doc for NEWFALSE. (GH-9432)

Also make docs for NEWFALSE and NEWTRUE more consistent
with docs for other opcodes.
(cherry picked from commit 488cfb7)

Co-authored-by: Krzysztof Wroblewski <krzysiek.wr@gmail.com>

Author: miss-islington

Lib/pickletools.py

@@ -1325,19 +1325,15 @@ def __init__(self, name, code, arg,
       stack_before=[],
       stack_after=[pybool],
       proto=2,
-      doc="""True.
-
-      Push True onto the stack."""),
+      doc="Push True onto the stack."),
 
     I(name='NEWFALSE',
       code='\x89',
       arg=None,
       stack_before=[],
       stack_after=[pybool],
       proto=2,
-      doc="""True.
-
-      Push False onto the stack."""),
+      doc="Push False onto the stack."),
 
     # Ways to spell Unicode strings.