Hi, thank you for creating such a great framework!
I have a feature request which I think I can contribute, but let me check if you are interested in supporting it.

### Preflight Checklist
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* [x] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
* [x] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
* [x] I have searched the issue tracker for a feature request that matches the one I want to file, without success.

### Problem Description
The builtin spellchecker has been supported in https://github.com/electron/electron/pull/20692.
But it does not allow us to check spells programmatically, like [node-spellchecker](https://github.com/felixrieseberg/node-spellchecker)'s `isMisspelled` method.
Chrome's spellcheck_platform provides [CheckSpelling](https://chromium.googlesource.com/chromium/src/+/46ee392970e491fb9ee2523348e23222b40d5119/components/spellcheck/browser/spellcheck_platform.h#60) to do that exactly.

### Proposed Solution
Add a method to call `spellcheck_platform::CheckSpelling` like so:

```cc
#if BUILDFLAG(USE_BROWSER_SPELLCHECKER)
bool Session::CheckSpelling(const std::string& word) {
  if (spellcheck::UseBrowserSpellChecker()) {
    return spellcheck_platform::CheckSpelling(base::UTF8ToUTF16(word), 0);
  }
  return true;
}
#endif
```

in `shell/browser/api/atom_api_session.cc`.

It's simple and won't affect other features.

### Alternatives Considered
I don't know.

### Additional Information
None

Thanks!
shell/renderer/api/electron_api_web_frame.cc
v8::Local<v8::Value> val,
                     blink::WebLocalFrame::ScriptExecutionType* out) {
    std::string execution_type;
    if (!ConvertFromV8(isolate, val, &execution_type))
      return false;
    if (execution_type == "asynchronous") {
      *out = blink::WebLocalFrame::kAsynchronous;
    } else if (execution_type == "asynchronousBlockingOnload") {
      *out = blink::WebLocalFrame::kAsynchronousBlockingOnload;
    } else if (execution_type == "synchronous") {
      *out = blink::WebLocalFrame::kSynchronous;
    } else {
      return false;
    }
    return true;
  }
};
template <>
struct Converter<blink::WebDocument::CSSOrigin> {
  static bool FromV8(v8::Isolate* isolate,