Tweaks to sys.flags description table.

The options listed in the table are now links to their documentation,
and the table uses compact markup to make it easier to read and edit.
First proposed in #10998.

Doc/library/sys.rst

@@ -206,31 +206,21 @@ always available.
    The struct sequence *flags* exposes the status of command line flags. The
    attributes are read only.
 
-   +------------------------------+------------------------------------------+
-   | attribute                    | flag                                     |
-   +==============================+==========================================+
-   | :const:`debug`               | -d                                       |
-   +------------------------------+------------------------------------------+
-   | :const:`division_warning`    | -Q                                       |
-   +------------------------------+------------------------------------------+
-   | :const:`inspect`             | -i                                       |
-   +------------------------------+------------------------------------------+
-   | :const:`interactive`         | -i                                       |
-   +------------------------------+------------------------------------------+
-   | :const:`optimize`            | -O or -OO                                |
-   +------------------------------+------------------------------------------+
-   | :const:`dont_write_bytecode` | -B                                       |
-   +------------------------------+------------------------------------------+
-   | :const:`no_user_site`        | -s                                       |
-   +------------------------------+------------------------------------------+
-   | :const:`no_site`             | -S                                       |
-   +------------------------------+------------------------------------------+
-   | :const:`ignore_environment`  | -E                                       |
-   +------------------------------+------------------------------------------+
-   | :const:`verbose`             | -v                                       |
-   +------------------------------+------------------------------------------+
-   | :const:`bytes_warning`       | -b                                       |
-   +------------------------------+------------------------------------------+
+   ============================= =============================
+   attribute                     flag
+   ============================= =============================
+   :const:`debug`                :option:`-d`
+   :const:`division_warning`     :option:`-Q`
+   :const:`inspect`              :option:`-i`
+   :const:`interactive`          :option:`-i`
+   :const:`optimize`             :option:`-O` or :option:`-OO`
+   :const:`dont_write_bytecode`  :option:`-B`
+   :const:`no_user_site`         :option:`-s`
+   :const:`no_site`              :option:`-S`
+   :const:`ignore_environment`   :option:`-E`
+   :const:`verbose`              :option:`-v`
+   :const:`bytes_warning`        :option:`-b`
+   ============================= =============================
 
 
 .. data:: float_info