minor #24969 Replace array|\Traversable by iterable (ro0NL)

This PR was merged into the 2.7 branch.

Discussion
----------

Replace array|\Traversable by iterable

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #... <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | symfony/symfony-docs#... <!--highly recommended for new features-->

Replace `array|\Traversable` by `iterable`, favoring pure API (or less mixed at least :)) and be clear whenever phpdoc is replaced.

https://secure.php.net/manual/en/language.types.iterable.php

Commits
-------

278088931b Replace array|\Traversable by iterable

Author: fabpot

Data/Bundle/Writer/TextBundleWriter.php

@@ -195,11 +195,11 @@ private function writeArray($file, array $value, $indentation)
     /**
      * Writes a "table" node.
      *
-     * @param resource           $file        The file handle to write to
-     * @param array|\Traversable $value       The value of the node
-     * @param int                $indentation The number of levels to indent
-     * @param bool               $fallback    Whether the table should be merged
-     *                                        with the fallback locale
+     * @param resource $file        The file handle to write to
+     * @param iterable $value       The value of the node
+     * @param int      $indentation The number of levels to indent
+     * @param bool     $fallback    Whether the table should be merged
+     *                              with the fallback locale
      *
      * @throws UnexpectedTypeException when $value is not an array and not a
      *                                 \Traversable instance