Copy RustOpenDocs command

See neovim/nvim-lspconfig#1921

plugin/lsp.lua

@@ -90,6 +90,20 @@ lspconfig.cmake.setup({
 lspconfig.rust_analyzer.setup({
   capabilities = capabilities,
   on_attach = on_attach,
+  commands = {
+    RustOpenDocs = {
+      function()
+        vim.lsp.buf_request(vim.api.nvim_get_current_buf(), 'experimental/externalDocs', vim.lsp.util.make_position_params(), function(err, url)
+          if err then
+            error(tostring(err))
+          else
+            vim.fn['netrw#BrowseX'](url, 0)
+          end
+        end)
+      end,
+      description = 'Open documentation for the symbol under the cursor in default browser',
+    },
+  },
 })
 lspconfig.pylsp.setup({
   capabilities = capabilities,