bpo-38738: Fix formatting of True and False. (GH-17083)

* "Return true/false" is replaced with "Return ``True``/``False``"
  if the function actually returns a bool.
* Fixed formatting of some True and False literals (now in monospace).
* Replaced "True/False" with "true/false" if it can be not only bool.
* Replaced some 1/0 with True/False if it corresponds the code.
* "Returns <bool>" is replaced with "Return <bool>".
diff --git a/Doc/library/parser.rst b/Doc/library/parser.rst
index e4d6d1d..79fc10d 100644
--- a/Doc/library/parser.rst
+++ b/Doc/library/parser.rst
@@ -234,8 +234,8 @@
 
    .. index:: builtin: compile
 
-   When *st* represents an ``'eval'`` form, this function returns true, otherwise
-   it returns false.  This is useful, since code objects normally cannot be queried
+   When *st* represents an ``'eval'`` form, this function returns ``True``, otherwise
+   it returns ``False``.  This is useful, since code objects normally cannot be queried
    for this information using existing built-in functions.  Note that the code
    objects created by :func:`compilest` cannot be queried like this either, and
    are identical to those created by the built-in :func:`compile` function.