Removed spaces before colons and semicolons.
diff --git a/Doc/library/rexec.rst b/Doc/library/rexec.rst
index 6b6923c..12f6faa 100644
--- a/Doc/library/rexec.rst
+++ b/Doc/library/rexec.rst
@@ -270,7 +270,7 @@
            if mode in ('r', 'rb'):
                pass
            elif mode in ('w', 'wb', 'a', 'ab'):
-               # check filename : must begin with /tmp/
+               # check filename: must begin with /tmp/
                if file[:5]!='/tmp/':
                    raise IOError("can't write outside /tmp")
                elif (string.find(file, '/../') >= 0 or