fix(lsp): explicitly set xref handlers for eglot

Otherwise a major mode's lookup handlers may take precedence (e.g. in
go-mode).

Close #5329

modules/tools/lsp/+eglot.el

@@ -17,6 +17,8 @@
   :config
   (set-popup-rule! "^\\*eglot-help" :size 0.15 :quit t :select t)
   (set-lookup-handlers! 'eglot--managed-mode
+    :definition      #'xref-find-definitions
+    :references      #'xref-find-references
     :implementations #'eglot-find-implementation
     :type-definition #'eglot-find-typeDefinition
     :documentation   #'+eglot-lookup-documentation)