Can I use the alternate search path and searchPath at the same time?

Hi, @jonkemp
I want to be able to find the path use `alternate search path` first and and the option `searchPath` is not undefined will to be used in next!
I change my local modules `getPattern.js` code:
```javascript
if (files[destPath].searchPaths && searchPath) {
if(searchPath.startsWith('{')){
searchPaths = path.resolve(cwd, searchPath.replace('{', '{' + files[destPath].searchPaths+','));
}else{
searchPaths = path.resolve(cwd, '{'+ files[destPath].searchPaths + ',' + searchPath +'}');
}
}else if (files[destPath].searchPaths || searchPath) {
searchPaths = path.resolve(cwd, files[destPath].searchPaths || searchPath);
}
```
It work fine for me.would you like to add the feature to the next version?

Start with getPattern.js and inspect how alternate search paths and the searchPath option are currently handled. Confirm that both paths can be used together in the requested order, then verify the resulting path resolution for each supported searchPath form.

Written by the indexing model from the issue text.