Issue #28496: Mark up constants 0, 1 and -1 that denote return values or
special input values as literal text.
diff --git a/Doc/c-api/import.rst b/Doc/c-api/import.rst
index 5a083ce..5273633 100644
--- a/Doc/c-api/import.rst
+++ b/Doc/c-api/import.rst
@@ -185,10 +185,10 @@
 
    Return the magic number for Python bytecode files (a.k.a. :file:`.pyc` file).
    The magic number should be present in the first four bytes of the bytecode
-   file, in little-endian byte order. Returns -1 on error.
+   file, in little-endian byte order. Returns ``-1`` on error.
 
    .. versionchanged:: 3.3
-      Return value of -1 upon failure.
+      Return value of ``-1`` upon failure.
 
 
 .. c:function:: const char * PyImport_GetMagicTag()