Document absoluteness of sys.executable
Closes #13402.
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 692805b..a0374fb 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -1093,7 +1093,7 @@
hexversion -- version information encoded as a single integer\n\
copyright -- copyright notice pertaining to this interpreter\n\
platform -- platform identifier\n\
-executable -- pathname of this Python interpreter\n\
+executable -- absolute path of the executable binary of the Python interpreter\n\
prefix -- prefix used to find the Python library\n\
exec_prefix -- prefix used to find the machine-specific Python library\n\
float_repr_style -- string indicating the style of repr() output for floats\n\