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 488cfb78)
Co-authored-by: Krzysztof Wroblewski <krzysiek.wr@gmail.com>

Lib/pickletools.py

@@ -1048,9 +1048,7 @@ opcodes = [
       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',
@@ -1058,9 +1056,7 @@ opcodes = [
       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.