Fix #196: run connection hooks with proper dir-locals

eglot-connect-hook and eglot-server-initialized-hook, must run in a
buffer with properly setup directory-local variables for the project,
so that things like eglot-signal-didChangeConfiguration can succeed.

I could have chosen any of the buffers where Eglot is activating
itself, but the approach using
hack-dir-local-variables-non-file-buffer seems more correct, despite
the name.

* eglot.el (eglot--connect): Run connection hooks with proper
dir-locals.

eglot.el

@@ -840,8 +840,10 @@ This docstring appeases checkdoc, that's all."
                                    (lambda ()
                                      (setf (eglot--inhibit-autoreconnect server)
                                            (null eglot-autoreconnect)))))))
-                          (run-hook-with-args 'eglot-connect-hook server)
-                          (run-hook-with-args 'eglot-server-initialized-hook server)
+                          (let ((default-directory (car (project-roots project))))
+                            (hack-dir-local-variables-non-file-buffer)
+                            (run-hook-with-args 'eglot-connect-hook server)
+                            (run-hook-with-args 'eglot-server-initialized-hook server))
                           (eglot--message
                            "Connected! Server `%s' now managing `%s' buffers \
 in project `%s'."