Clean up API docs for contextual module

Looks OK... one small thing to fix up:

+ * @file
+ * Attaches behaviors for contextual module.

When referring to a module, either say "Contextual module" or "contextual.module". The latter is somewhat preferred, as it becomes a link on api.drupal.org.

True about contextual.module referring to the module file itself. In that case, capitalize and use "the": "the Contextual module".

This needs a newline after the @file docblock:

+/**
+ * @file
+ * Attaches behaviors for Contextual module.
+ */
+
 (function ($) {

And the word "the", and we're good to go.

Regarding where the convention for modules is documented.... We enforced this convention extensively during the D7 cycle when we overhauled the core modules' hook_help(), and I'm sure we put it in the instructions for how to write a hook_help() (wherever that is...), but it didn't make it to the general writing style guide. So I just added it:
http://drupal.org/style-guide/content#moduleref
Sorry about that!

Oh, here's the standard for hook_help that we wrote, which includes (but does not explicitly state) this standard (the example is from the node module, but we don't really explain the standard):
http://drupal.org/node/632280

It's a relief to see a short module. :) Looked it over and noticed a few things:

• Looks to me like contextual_pre_render_links() is a pre-render callback registered in contextual_element_info(), so maybe we should document that?

  See http://drupal.org/node/1354#callbacks. We don't have a particular standard for Render API yet, but I've used the pattern "Pre-render callback: Foos a bar." for the one-line summaries in #1315886: Clean up API docs for includes directory, files starting with A-C.

• Looks also like Drupal.behaviors.contextualLinks just needs a verb tense change.
• The CSS file are also also missing @file blocks.

+++ b/core/modules/contextual/contextual-rtl.cssundefined
@@ -1,4 +1,8 @@
-
+/**
+ * @file
+ * Stylesheet specific to right-to-left languages.
+ */
+ ¶

There's one bit of trailing whitespace here. Other than that, I think this patch is ready.

Looks good.

RE #13 - if you do not leave a blank line after the @file docblock, it becomes the docblock for the next thing in the file, which in this case is an (undocumented) variable or function. I don't really think we need to add that to the standards page?

OK. I edited node/1354 to make this hopefully a little clearer (both the general section at the top and the file section).

Looks good, seems like this could be backported to D7 as well, minus that "Pre-render callback:" bit.

So, committed and pushed to 8.x (in full) and 7.x (with that hunk reverted).