lsp-format-region: Fix error "no region" (#4827)

Author: sunlin7

lsp-mode.el

@@ -6294,7 +6294,10 @@ one or more symbols, and STRUCTURE should be compatible with
 
 (defun lsp-format-region (s e)
   "Ask the server to format the region, or if none is selected, the current line."
-  (interactive "r")
+  (interactive
+   (if (use-region-p)
+       (list (region-beginning) (region-end))
+     (list (point) (point))))
   (let ((edits (lsp-request
                 "textDocument/rangeFormatting"
                 (lsp--make-document-range-formatting-params s e))))