Let JSHint know that the `show_details` function is an exported global

Summary:
The `show_details` function is used by DarkConsole. Adding this comment silences the following JSHint warning:

```
>>> Lint for webroot/rsrc/js/core/behavior-error-log.js:

   Warning  (W098) JSHintW098
    'show_details' is defined but never used.

               5
               6 var current_details = null;
               7
    >>>        8 function show_details(row) {
               9   var node = JX.$('row-details-' + row);
              10
              11   if (current_details !== null) {
```

Test Plan: `arc lint`

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11063