minor symfony#6980 Use strict comparison (greg0ire)

This PR was merged into the 2.7 branch.

Discussion
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Use strict comparison

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2c1986f Use strict comparison

Author: xabbuh

setup/bundles.rst

@@ -173,7 +173,7 @@ Before diving into the specifics of the most common edge cases, the general
 recommendation is to **not rely on the Symfony Kernel version** to decide which
 code to use::
 
-    if (Kernel::VERSION_ID <= 20800) {
+    if (Kernel::VERSION_ID < 20800) {
         // code for Symfony 2.x
     } else {
         // code for Symfony 3.x