bug #2899 Fixed spaceless filter (tifabien)

This PR was merged into the 1.x branch.

Discussion
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Fixed spaceless filter

As now the `spaceless` tag is deprecated, I tried to replace it by the new `spaceless` filter instead but it broke my application. Actually there is a difference between the tag and the filter. Spaceless tag trim also whistespace (or line feed).

I propose to do the same thing on the new filter.

Commits
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3412d1a5 Fixed spaceless filter

src/Extension/CoreExtension.php

@@ -997,7 +997,7 @@ function twig_trim_filter($string, $characterMask = null, $side = 'both')
  */
 function twig_spaceless($content)
 {
-    return preg_replace('/>\s+</', '><', $content);
+    return trim(preg_replace('/>\s+</', '><', $content));
 }
 
 /**