📝 Add missing document entrypoints

Author: lambdalisue

denops_std/README.md

@@ -58,6 +58,8 @@ for more details.
 | -------------------------- | ---------------------------------------------------------------- |
 | [`anonymous`](./anonymous) | A module to provide anonymous function                           |
 | [`autocmd`](./autocmd)     | A module to provide helper functions to manage `autocmd`         |
+| [`batch`](./batch)         | A module to provide wrapper functions of `denops.batch()`        |
 | [`function`](./function)   | A module to provide functions of Vim and Neovim native functions |
 | [`helper`](./helper)       | A module to provide helper functions                             |
+| [`mapping`](./mapping)     | A module to provide helper functions to manage mappings          |
 | [`variable`](./variable)   | A module to provide helper accessor functions to variables       |