doc: update KYAML doc to beta stage updates

Signed-off-by: rxinui <[email protected]>

Author: rxinui

content/en/docs/reference/kubectl/_index.md

@@ -270,7 +270,7 @@ Output format | Description
 `-o json`     | Output a JSON formatted API object.
 `-o jsonpath=<template>` | Print the fields defined in a [jsonpath](/docs/reference/kubectl/jsonpath/) expression.
 `-o jsonpath-file=<filename>` | Print the fields defined by the [jsonpath](/docs/reference/kubectl/jsonpath/) expression in the `<filename>` file.
-`-o kyaml`    | Output a KYAML formatted API object (alpha, requires environment variable `KUBECTL_KYAML="true"`).
+`-o kyaml`    | Output a KYAML formatted API object (beta).
 `-o name`     | Print only the resource name and nothing else.
 `-o wide`     | Output in the plain-text format with any additional information. For pods, the node name is included.
 `-o yaml`     | Output a YAML formatted API object. KYAML is an experimental Kubernetes-specific dialect of YAML, and can be parsed as YAML.

content/en/docs/reference/kubectl/quick-reference.md

@@ -461,7 +461,7 @@ Output format | Description
 `-o=json`     | Output a JSON formatted API object
 `-o=jsonpath=<template>` | Print the fields defined in a [jsonpath](/docs/reference/kubectl/jsonpath) expression
 `-o=jsonpath-file=<filename>` | Print the fields defined by the [jsonpath](/docs/reference/kubectl/jsonpath) expression in the `<filename>` file
-`-o=kyaml`    | Output a KYAML formatted API object (alpha, requires environment variable `KUBECTL_KYAML="true"`). KYAML is an experimental Kubernetes-specific dialect of YAML, and can be parsed as YAML.
+`-o=kyaml` (beta) | Output a KYAML formatted API object. KYAML is an Kubernetes-specific dialect of YAML, and can be parsed as YAML.
 `-o=name`     | Print only the resource name and nothing else
 `-o=wide`     | Output in the plain-text format with any additional information, and for pods, the node name is included
 `-o=yaml`     | Output a YAML formatted API object