docs: add GitHub buttons and improve option docs

src/liquid-options.ts

@@ -72,7 +72,7 @@ export interface LiquidOptions {
   fs?: FS;
   /** keyValue separator */
   keyValueSeparator?: string;
-  /** Render from in-memory `templates` mapping instead of file system. File system related options like `fs`, 'root', and `relativeReference` will be ignored when `templates` is specified. */
+  /** Render from an in-memory `templates` mapping instead of the file system. When `templates` is set, Liquid uses the provided mapping for template lookup (including includes, layouts, and partials), and file-system options such as `fs`, `root`, `partials`, `layouts`, and `relativeReference` are effectively bypassed for those lookups. */
   templates?: {[key: string]: string};
   /** the global scope passed down to all partial and layout templates, i.e. templates included by `include`, `layout` and `render` tags. */
   globals?: object;