[EarlyReturn] Deprecate ChangeNestedForeachIfsToEarlyContinueRector

[TomasVotruba]

Deprecates ChangeNestedForeachIfsToEarlyContinueRector.

Inverting nested ifs into continue guards makes the code harder to read and understand. Whether the early-continue shape is better depends on the surrounding context, which the rule cannot know.

 foreach ($values as $value) {
-    if ($value === 5) {
-        if ($value2 === 10) {
-            $items[] = 'maybe';
-        }
-    }
+    if ($value !== 5) {
+        continue;
+    }
+    if ($value2 !== 10) {
+        continue;
+    }
+
+    $items[] = 'maybe';
 }

The rule now implements DeprecatedInterface and throws on use. It is removed from the early-return set, and its tests are dropped.

Also removes IfManipulator::collectNestedIfsWithNonBreaking(), its only caller.