chore: add DISABLE_WEB_PAGE_PREVIEW docs

DOCS.md

@@ -225,6 +225,18 @@ Example configuration with a custom socks5 URL:
 +     socks5: socks5://67.204.21.1:64312
 ```
 
+Disables link previews for links in this message
+
+```diff
+  - name: send telegram notification
+    image: appleboy/drone-telegram
+    settings:
+      token: xxxxxxxxxx
+      to: telegram_user_id
+      message: send message using custom socks5 URL
++     disable_web_page_preview: true
+```
+
 ## Parameter Reference
 
 token

main.go

@@ -112,7 +112,7 @@ func main() {
 		cli.BoolFlag{
 			Name:   "disable.webpage.preview",
 			Usage:  "disables link previews for links in this message",
-			EnvVar: "PLUGIN_WEBPAGE_PREVIEW,INPUT_DISABLE_WEB_PAGE_PREVIEW",
+			EnvVar: "PLUGIN_DISABLE_WEB_PAGE_PREVIEW,INPUT_DISABLE_WEB_PAGE_PREVIEW",
 		},
 		cli.StringFlag{
 			Name:   "format",