Document CodeType.replace (GH-17776)

diff --git a/Objects/clinic/codeobject.c.h b/Objects/clinic/codeobject.c.h
index 6596de0..1dd8227 100644
--- a/Objects/clinic/codeobject.c.h
+++ b/Objects/clinic/codeobject.c.h
@@ -11,7 +11,7 @@
 "        co_lnotab=None)\n"
 "--\n"
 "\n"
-"Return a new code object with new specified fields.");
+"Return a copy of the code object with new values for the specified fields.");
 
 #define CODE_REPLACE_METHODDEF    \
     {"replace", (PyCFunction)(void(*)(void))code_replace, METH_FASTCALL|METH_KEYWORDS, code_replace__doc__},
@@ -253,4 +253,4 @@
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=fade581d6313a0c2 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=27fe34e82106b220 input=a9049054013a1b77]*/