Merge pull request #51416 from HirazawaUi/add-doc-4369

Add documentation for graduating the RelaxedEnvironmentVariableValidation to GA.

Author: k8s-ci-robot

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

@@ -13,5 +13,11 @@ stages:
   - stage: beta
     defaultValue: true
     fromVersion: "1.32"
+    toVersion: "1.33"
+  - stage: stable
+    defaultValue: true
+    locked: true
+    fromVersion: "1.34"
+    
 ---
 Allow almost all printable ASCII characters in environment variables.

content/en/docs/tasks/inject-data-application/define-environment-variable-container.md

@@ -102,10 +102,7 @@ Honorable`, and `Kubernetes`, respectively. The environment variable
 `MESSAGE` combines the set of all these environment variables and then uses it 
 as a CLI argument passed to the `env-print-demo` container.
 
-Environment variable names consist of letters, numbers, underscores,
-dots, or hyphens, but the first character cannot be a digit.
-If the `RelaxedEnvironmentVariableValidation` [feature gate](/docs/reference/command-line-tools-reference/feature-gates/) is enabled,
-all [printable ASCII characters](https://www.ascii-code.com/characters/printable-characters) except "=" may be used for environment variable names.
+Environment variable names may consist of any [printable ASCII characters](https://www.ascii-code.com/characters/printable-characters) except '='.
 
 ```yaml
 apiVersion: v1