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
dict.SetMethod("getZoomLevel", &GetZoomLevel);
  dict.SetMethod("setZoomFactor", &SetZoomFactor);
  dict.SetMethod("getZoomFactor", &GetZoomFactor);
  dict.SetMethod("setVisualZoomLevelLimits", &SetVisualZoomLevelLimits);
  dict.SetMethod("allowGuestViewElementDefinition",
                 &AllowGuestViewElementDefinition);
  dict.SetMethod("getWebFrameId", &GetWebFrameId);
  dict.SetMethod("setSpellCheckProvider", &SetSpellCheckProvider);
  dict.SetMethod("insertText", &InsertText);
  dict.SetMethod("insertCSS", &InsertCSS);
  dict.SetMethod("removeInsertedCSS", &RemoveInsertedCSS);
  dict.SetMethod("executeJavaScript", &ExecuteJavaScript);
  dict.SetMethod("executeJavaScriptInIsolatedWorld",
                 &ExecuteJavaScriptInIsolatedWorld);
  dict.SetMethod("setIsolatedWorldInfo", &SetIsolatedWorldInfo);
  dict.SetMethod("getResourceUsage", &GetResourceUsage);
  dict.SetMethod("clearCache", &ClearCache);
  dict.SetMethod("_findFrameByRoutingId", &FindFrameByRoutingId);
  dict.SetMethod("_getFrameForSelector", &GetFrameForSelector);
  dict.SetMethod("_findFrameByName", &FindFrameByName);
  dict.SetMethod("_getOpener", &GetOpener);
  dict.SetMethod("_getParent", &GetFrameParent);
  dict.SetMethod("_getTop", &GetTop);
  dict.SetMethod("_getFirstChild", &GetFirstChild);
  dict.SetMethod("_getNextSibling", &GetNextSibling);
  dict.SetMethod("_getRoutingId", &GetRoutingId);
}
}  
NODE_LINKED_MODULE_CONTEXT_AWARE(electron_renderer_web_frame, Initialize)