Correct two versionchanged directives, to improve the 'changes' output

Doc/library/py_compile.rst

@@ -46,8 +46,7 @@ files named on the command line.  The exit status is nonzero if one of the files
 could not be compiled.
 
 .. versionchanged:: 2.6
-
-   Added the nonzero exit status.
+   Added the nonzero exit status when module is run as a script.
 
 
 .. seealso::

Doc/library/zlib.rst

@@ -44,9 +44,9 @@ The available exception and functions in this module are:
 
    This function always returns an integer object.
 
-.. versionchanged:: 2.6
-   For consistent cross-platform behavior we always return a signed integer.
-   ie: Results in the (2**31)...(2**32-1) range will be negative.
+   .. versionchanged:: 2.6
+     For consistent cross-platform behavior we always return a signed integer.
+     ie: Results in the (2**31)...(2**32-1) range will be negative.
 
 
 .. function:: compress(string[, level])
@@ -82,9 +82,9 @@ The available exception and functions in this module are:
 
    This function always returns an integer object.
 
-.. versionchanged:: 2.6
-   For consistent cross-platform behavior we always return a signed integer.
-   ie: Results in the (2**31)...(2**32-1) range will be negative.
+   .. versionchanged:: 2.6
+     For consistent cross-platform behavior we always return a signed integer.
+     ie: Results in the (2**31)...(2**32-1) range will be negative.
 
 
 .. function:: decompress(string[, wbits[, bufsize]])