KEP-5142: Add SchedulerPopFromBackoffQ feature gate docs

Author: macsko

content/en/docs/reference/command-line-tools-reference/feature-gates/SchedulerPopFromBackoffQ.md

@@ -0,0 +1,15 @@
+---
+title: SchedulerPopFromBackoffQ
+content_type: feature_gate
+_build:
+  list: never
+  render: false
+
+stages:
+  - stage: beta
+    defaultValue: true
+    fromVersion: "1.33"
+---
+
+Improves scheduling queue behavior by popping pods from the backoffQ when the activeQ is empty.
+This allows to process potentially schedulable pods ASAP, eliminating a penalty effect of the backoff queue.