doc: mark .env files support as stable

As discussed in the referenced issue the feature should be ready to be
marked as stable.

Refs: #49148 (comment)
PR-URL: #59925
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>

Author: Hilzu

doc/api/cli.md

@@ -815,10 +815,12 @@ node --entry-url 'data:text/javascript,console.log("Hello")'
 
 <!-- YAML
 added: v22.9.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/59925
+    description: The `--env-file-if-exists` flag is no longer experimental.
 -->
 
-> Stability: 1.1 - Active development
-
 Behavior is the same as [`--env-file`][], but an error is not thrown if the file
 does not exist.
 
@@ -827,15 +829,16 @@ does not exist.
 <!-- YAML
 added: v20.6.0
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/59925
+    description: The `--env-file` flag is no longer experimental.
   - version:
     - v21.7.0
     - v20.12.0
     pr-url: https://github.com/nodejs/node/pull/51289
     description: Add support to multi-line values.
 -->
 
-> Stability: 1.1 - Active development
-
 Loads environment variables from a file relative to the current directory,
 making them available to applications on `process.env`. The [environment
 variables which configure Node.js][environment_variables], such as `NODE_OPTIONS`,

doc/api/environment_variables.md

@@ -18,7 +18,7 @@ For more details refer to the [`process.env` documentation][].
 
 Set of utilities for dealing with additional environment variables defined in `.env` files.
 
-> Stability: 1.1 - Active development
+> Stability: 2 - Stable
 
 <!--introduced_in=v20.12.0-->
 

doc/api/process.md

@@ -2779,10 +2779,12 @@ debugger. See [Signal Events][].
 added:
   - v21.7.0
   - v20.12.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/59925
+    description: This API is no longer experimental.
 -->
 
-> Stability: 1.1 - Active development
-
 * `path` {string | URL | Buffer | undefined}. **Default:** `'./.env'`
 
 Loads the `.env` file into `process.env`. Usage of `NODE_OPTIONS`

doc/api/util.md

@@ -2188,10 +2188,12 @@ $ node negate.js --no-logfile --logfile=test.log --color --no-color
 added:
   - v21.7.0
   - v20.12.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/59925
+    description: This API is no longer experimental.
 -->
 
-> Stability: 1.1 - Active development
-
 * `content` {string}
 
 The raw contents of a `.env` file.