off-by-one error in publishDiagnostics handler

[adonovan]

I think there's an off-by-one error in the publishDiagnostics. When a server-reported diagnostic has an empty range (the same value for begin and end) the logic falls back to flymake-diag-region, but it forgets to convert the 0-based LSP character index to the 1-based column number conventionally used by Emacs. (It also doesn't transcode UTF-16 to code points, but that's ok.)

If I'm right, the fix is this:

(cl-defmethod eglot-handle-notification
  (_server (_method (eql textDocument/publishDiagnostics)) &key uri diagnostics
           &allow-other-keys) ; FIXME: doesn't respect `eglot-strict-mode'
  "Handle notification publishDiagnostics."
...
                       ;; Fallback to `flymake-diag-region' if server
                       ;; botched the range
                       (when (= beg end)
                         (if-let* ((st (plist-get range :start))
                                   (diag-region
                                    (flymake-diag-region
                                     (current-buffer) (1+ (plist-get st :line))
-				     (plist-get st :character))))
+				     (1+ (plist-get st :character)))))
                             (setq beg (car diag-region) end (cdr diag-region))
                           (eglot--widening
                            (goto-char (point-min))
                            (setq beg
                                  (eglot--bol
                                   (1+ (plist-get (plist-get range :start) :line))))
                            (setq end
                                  (line-end-position
                                   (1+ (plist-get (plist-get range :end) :line)))))))
...

Should I send a patch?