Add template function descriptions

plugins/template-function-fs/src/index.ts

@@ -4,6 +4,7 @@ import fs from 'node:fs';
 export const plugin: PluginDefinition = {
   templateFunctions: [{
     name: 'fs.readFile',
+    description: 'Read the contents of a file as utf-8',
     args: [{ title: 'Select File', type: 'file', name: 'path', label: 'File' }],
     async onRender(_ctx: Context, args: CallTemplateFunctionArgs): Promise<string | null> {
       if (!args.values.path) return null;