doc: fix --env-file docs for valid quotes for defining values

PR-URL: #52157
Reviewed-By: Antoine du Hamel <[email protected]>
Reviewed-By: Ulises Gascón <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>

Author: dygabo

doc/api/cli.md

@@ -688,7 +688,7 @@ Any text after a `#` is treated as a comment:
 PORT=3000 # This is also a comment
 ```
 
-Values can start and end with the following quotes: `\`, `"` or `'`.
+Values can start and end with the following quotes: `` ` ``, `"` or `'`.
 They are omitted from the values.
 
 ```text