bpo-29770: remove outdated PYO related info (GH-590) (GH-612)

diff --git a/Modules/zipimport.c b/Modules/zipimport.c
index 59046aa..cccc033 100644
--- a/Modules/zipimport.c
+++ b/Modules/zipimport.c
@@ -1102,7 +1102,7 @@
     _Py_IDENTIFIER(decompress);
 
     if (importing_zlib != 0)
-        /* Someone has a zlib.py[co] in their Zip file;
+        /* Someone has a zlib.pyc in their Zip file;
            let's avoid a stack overflow. */
         return NULL;
     importing_zlib = 1;
@@ -1261,7 +1261,7 @@
     return d <= 1;
 }
 
-/* Given the contents of a .py[co] file in a buffer, unmarshal the data
+/* Given the contents of a .pyc file in a buffer, unmarshal the data
    and return the code object. Return None if it the magic word doesn't
    match (we do this instead of raising an exception as we fall back
    to .py if available and we don't want to mask other errors).
@@ -1403,7 +1403,7 @@
     PyObject *toc_entry, *stripped;
     time_t mtime;
 
-    /* strip 'c' or 'o' from *.py[co] */
+    /* strip 'c' from *.pyc */
     if (PyUnicode_READY(path) == -1)
         return (time_t)-1;
     stripped = PyUnicode_FromKindAndData(PyUnicode_KIND(path),