table wp-calendar should include summary atribute

[don_ousian]

As a part of Web Content Accessibility Guidelines 1.0,
content generatos should provide summaries for tables.
​WCAG checkpoint 5.5

I often try to make my blog accesible enough, and since version 1.0.something
I've modified this little piece of code by myself. It'll only afect wcag level 3.

It's just something like:
echo '<table id="wp-calendar" summary="_e(whatever...)"> ... in general-template.php:497.

[rob1n]

We already set summary="Calendar"...

[rob1n]

We already set it to a translated "Calendar." If you want it to be more, open this ticket again with more specific information.