Revert "feat(lsp): support version in textDocument/publishDiagnostics #36754" (#36865)

This reverts commit 03d6cf7aae.

See https://github.com/neovim/neovim/pull/36754#issuecomment-3626115697
The change was supposed to avoid showing stale diagnostics but had the
opposite effect.

runtime/lua/vim/lsp/diagnostic.lua

@@ -222,8 +222,7 @@ end
 --- @param client_id? integer
 --- @param diagnostics lsp.Diagnostic[]
 --- @param is_pull boolean
---- @param version integer?
-local function handle_diagnostics(uri, client_id, diagnostics, is_pull, version)
+local function handle_diagnostics(uri, client_id, diagnostics, is_pull)
   local fname = vim.uri_to_fname(uri)
 
   if #diagnostics == 0 and vim.fn.bufexists(fname) == 0 then
@@ -235,10 +234,6 @@ local function handle_diagnostics(uri, client_id, diagnostics, is_pull, version)
     return
   end
 
-  if version and util.buf_versions[bufnr] ~= version then
-    return
-  end
-
   client_id = client_id or DEFAULT_CLIENT_ID
 
   local namespace = M.get_namespace(client_id, is_pull)
@@ -254,7 +249,7 @@ end
 ---@param params lsp.PublishDiagnosticsParams
 ---@param ctx lsp.HandlerContext
 function M.on_publish_diagnostics(_, params, ctx)
-  handle_diagnostics(params.uri, ctx.client_id, params.diagnostics, false, params.version)
+  handle_diagnostics(params.uri, ctx.client_id, params.diagnostics, false)
 end
 
 --- |lsp-handler| for the method "textDocument/diagnostic"

runtime/lua/vim/lsp/protocol.lua

@@ -559,7 +559,6 @@ function protocol.make_client_capabilities()
           valueSet = get_value_set(constants.DiagnosticTag),
         },
         dataSupport = true,
-        versionSupport = true,
       },
       callHierarchy = {
         dynamicRegistration = false,