bpo-33877: Remove UNIX qualification for running complete programs (GH-7744)

The statement is true for Windows (and macOS) also.
diff --git a/Doc/reference/toplevel_components.rst b/Doc/reference/toplevel_components.rst
index e1687ff..d5ffb37 100644
--- a/Doc/reference/toplevel_components.rst
+++ b/Doc/reference/toplevel_components.rst
@@ -48,14 +48,15 @@
 
 .. index::
    single: UNIX
+   single: Windows
    single: command line
    single: standard input
 
-Under Unix, a complete program can be passed to the interpreter in three forms:
-with the :option:`-c` *string* command line option, as a file passed as the
-first command line argument, or as standard input.  If the file or standard
-input is a tty device, the interpreter enters interactive mode; otherwise, it
-executes the file as a complete program.
+A complete program can be passed to the interpreter
+in three forms: with the :option:`-c` *string* command line option, as a file
+passed as the first command line argument, or as standard input.  If the file
+or standard input is a tty device, the interpreter enters interactive mode;
+otherwise, it executes the file as a complete program.
 
 
 .. _file-input: