fix: show deprecation messages on_init

CONTRIBUTING.md

@@ -132,12 +132,17 @@ If a config needs to be renamed or deprecated, changes its contents like this:
 ```lua
 ---@brief
 ---
---- Renamed to [vsrocq](#vsrocq)
-
-vim.deprecate('vscoqtop', 'vsrocq', '2.0.0', 'nvim-lspconfig', false)
+--- Renamed to [systemd_lsp](#systemd_lsp)
 
 ---@type vim.lsp.Config
-return vim.lsp.config.vsrocq
+return vim.tbl_extend('force', vim.lsp.config.systemd_lsp, {
+  on_init = function(...)
+    vim.deprecate('systemd_ls', 'systemd_lsp', '3.0.0', 'nvim-lspconfig', false)
+    if vim.lsp.config.systemd_lsp.on_init then
+      vim.lsp.config.systemd_lsp.on_init(...)
+    end
+  end,
+})
 ```
 
 ## Commit style

lsp/systemd_ls.lua

@@ -2,7 +2,12 @@
 ---
 --- Renamed to [systemd_lsp](#systemd_lsp)
 
-vim.deprecate('systemd_ls', 'systemd_lsp', '2.0.0', 'nvim-lspconfig', false)
-
 ---@type vim.lsp.Config
-return vim.lsp.config.systemd_lsp
+return vim.tbl_extend('force', vim.lsp.config.systemd_lsp, {
+  on_init = function(...)
+    vim.deprecate('systemd_ls', 'systemd_lsp', '3.0.0', 'nvim-lspconfig', false)
+    if vim.lsp.config.systemd_lsp.on_init then
+      vim.lsp.config.systemd_lsp.on_init(...)
+    end
+  end,
+})

lsp/volar.lua

@@ -1,9 +1,13 @@
 ---@brief
 ---
 --- Renamed to [vue_ls](#vue_ls)
----
----
-vim.deprecate('volar', 'vue_ls', '3.0.0', 'nvim-lspconfig', false)
 
 ---@type vim.lsp.Config
-return vim.lsp.config.vue_ls
+return vim.tbl_extend('force', vim.lsp.config.vue_ls, {
+  on_init = function(...)
+    vim.deprecate('volar', 'vue_ls', '3.0.0', 'nvim-lspconfig', false)
+    if vim.lsp.config.vue_ls.on_init then
+      vim.lsp.config.vue_ls.on_init(...)
+    end
+  end,
+})

lsp/vscoqtop.lua

@@ -2,7 +2,12 @@
 ---
 --- Renamed to [vsrocq](#vsrocq)
 
-vim.deprecate('vscoqtop', 'vsrocq', '2.0.0', 'nvim-lspconfig', false)
-
 ---@type vim.lsp.Config
-return vim.lsp.config.vsrocq
+return vim.tbl_extend('force', vim.lsp.config.vsrocq, {
+  on_init = function(...)
+    vim.deprecate('vscoqtop', 'vsrocq', '3.0.0', 'nvim-lspconfig', false)
+    if vim.lsp.config.vsrocq.on_init then
+      vim.lsp.config.vsrocq.on_init(...)
+    end
+  end,
+})