feat: mark EnvHttpProxyAgent as stable (nodejs#4049)

* docs: mark `EnvHttpProxyAgent` as stable

* remove experimental warning

Author: aduh95

docs/docs/api/EnvHttpProxyAgent.md

@@ -1,7 +1,5 @@
 # Class: EnvHttpProxyAgent
 
-Stability: Experimental.
-
 Extends: `undici.Dispatcher`
 
 EnvHttpProxyAgent automatically reads the proxy configuration from the environment variables `http_proxy`, `https_proxy`, and `no_proxy` and sets up the proxy agents accordingly. When `http_proxy` and `https_proxy` are set, `http_proxy` is used for HTTP requests and `https_proxy` is used for HTTPS requests. If only `http_proxy` is set, `http_proxy` is used for both HTTP and HTTPS requests. If only `https_proxy` is set, it is only used for HTTPS requests.

lib/dispatcher/env-http-proxy-agent.js

@@ -10,8 +10,6 @@ const DEFAULT_PORTS = {
   'https:': 443
 }
 
-let experimentalWarned = false
-
 class EnvHttpProxyAgent extends DispatcherBase {
   #noProxyValue = null
   #noProxyEntries = null
@@ -21,13 +19,6 @@ class EnvHttpProxyAgent extends DispatcherBase {
     super()
     this.#opts = opts
 
-    if (!experimentalWarned) {
-      experimentalWarned = true
-      process.emitWarning('EnvHttpProxyAgent is experimental, expect them to change at any time.', {
-        code: 'UNDICI-EHPA'
-      })
-    }
-
     const { httpProxy, httpsProxy, noProxy, ...agentOpts } = opts
 
     this[kNoProxyAgent] = new Agent(agentOpts)