Use eglot--dbind and eglot--lambda throughout

Use eglot--dbind and eglot--lambda throughout

The default behaviour of these macros is to be lenient towards servers
sending unknown keys, which should fix the issue.

* eglot.el (eglot--lsp-interface-alist): Add a bunch of new interfaces.
(eglot--connect, eglot-handle-notification)
(xref-backend-identifier-completion-table)
(xref-backend-definitions, xref-backend-apropos)
(xref-backend-references, eglot-completion-at-point)
(eglot--sig-info, eglot-help-at-point, eglot-eldoc-function)
(eglot-imenu, eglot--apply-text-edits)
(eglot--apply-workspace-edit)
(eglot--register-workspace/didChangeWatchedFiles): Use
eglot--dbind and eglot--lambda to destructure LSP objects.

GitHub-reference: fix https://github.com/joaotavora/eglot/issues/144