minor #20176 [FrameworkBundle] Lower uppercase must (alexandre-daubois)

This PR was merged into the 5.4 branch.

Discussion
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[FrameworkBundle] Lower uppercase `must`

Just came across this one and it felt out of place. We tend to avoid "must". Even if I agree it is required in this situation, let's use bold instead of uppercase, feels less aggressive 🙂

Commits
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f4a552b [FrameworkBundle] Lower uppercase `must`

Author: javiereguiluz

reference/configuration/framework.rst

@@ -3268,7 +3268,7 @@ settings from the base pool as defaults.
 
 .. note::
 
-    Your service MUST implement the ``Psr\Cache\CacheItemPoolInterface`` interface.
+    Your service **must** implement the ``Psr\Cache\CacheItemPoolInterface`` interface.
 
 public
 """"""