doc: clarify ERR_FS_FILE_TOO_LARGE to reflect fs.readFile() I/O limit

PR-URL: #59050
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: LiviaMedeiros <[email protected]>

Author: haramj

doc/api/errors.md

@@ -1362,8 +1362,10 @@ Path is a directory.
 
 ### `ERR_FS_FILE_TOO_LARGE`
 
-An attempt has been made to read a file whose size is larger than the maximum
-allowed size for a `Buffer`.
+An attempt was made to read a file larger than the supported 2 GiB limit for
+`fs.readFile()`. This is not a limitation of `Buffer`, but an internal I/O constraint.
+For handling larger files, consider using `fs.createReadStream()` to read the
+file in chunks.
 
 <a id="ERR_FS_WATCH_QUEUE_OVERFLOW"></a>