Adds an `item_spacing` option to the arguments array for the functions `wp_nav_menu()`, `wp_list_pages()`, and `wp_page_menu()`. `item_spacing` is a boolean accepting either `preserve` or `discard`.
Previously, certain CSS choices could result in a site's layout changing if `wp_nav_menu()` fell back to the default `wp_list_pages()` due to differences in the whitespace within the HTML. The new argument ensures a function outputs consistant HTML while maintaining backward compatibility.
Fixes#35206.
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git-svn-id: http://core.svn.wordpress.org/trunk@38464 1a063a9b-81f0-0310-95a4-ce76da25c4cd
