docs: fix wrong description (#50774)

The descriptions had `i <= 5` while the code block had `i <=3`.

doc/src/manual/control-flow.md

@@ -397,7 +397,7 @@ julia> while i <= 3
 3
 ```
 
-The `while` loop evaluates the condition expression (`i <= 5` in this case), and as long it remains
+The `while` loop evaluates the condition expression (`i <= 3` in this case), and as long it remains
 `true`, keeps also evaluating the body of the `while` loop. If the condition expression is `false`
 when the `while` loop is first reached, the body is never evaluated.