Update remix_plugin_api.md

docs/remix_plugin_api.md

@@ -47,5 +47,13 @@ This section list all the available key and value pair which define this API:
  - getAccounts `@return {Array} acccounts`
  - createVMAccount `@param {String} privateKey, @param {String} balance (hex)`
 
+### editor
+ - getCurrentFile `@return {String} current file path displayed in the editor`
+ - getFile `@param {String} path, @return {String} content`
+ - setFile `@param {String} path, @param {String} content`
+ - highlight `@param {Object} lineColumnPos, @param {String} filePath, @param {String} hexColor `
+ 
+ 
+