added documentation in README

README.md

@@ -192,6 +192,7 @@ lsp-bridge provides support for more than two language servers for many language
 - `lsp-bridge-symbols-enable-which-func`: Using lsp backend for `which-func`, disable by default
 - `lsp-bridge-enable-org-babel`: Use lsp completion in org babel, disable by default, if unable to complete, please make sure the string after begin_src exists in the `org-src-lang-modes` variable
 - `lsp-bridge-peek-file-content-height`: Display how many lines of file content in peek windows
+- `lsp-bridge-peek-file-content-scroll-margin`: Set how many lines of file content should be scroll up and down.
 - `lsp-bridge-peek-list-height`: Select the next option for definition and reference
 - `lsp-bridge-peek-ace-keys`: Keys to press when performing `lsp-bridge-peek-through`
 - `lsp-bridge-peek-ace-cancel-keys`: Keys to exit `lsp-bridge-peek-through`