fix(context): update HTMLRespond type

[rossrobino]

If you pass anything with a toString method into c.html it will return the result, but the types don't currently reflect this.

This PR adds a HasToString type as an option for the first argument of c.html.

This enables you to do things like this and not have TS errors. Right now this works but TS errors.

const app = new Hono();

app.get("/number", (c) => c.html(1));

const obj = { toString: () => "hello world" };

app.get("/hello", (c) => c.html(obj));

No overload matches this call.
  Overload 1 of 2, '(html: string | Promise<string>, status?: StatusCode | undefined, headers?: HeaderRecord | undefined): Response | Promise<Response>', gave the following error.
    Argument of type 'number' is not assignable to parameter of type 'string | Promise<string>'.
  Overload 2 of 2, '(html: string | Promise<string>, init?: ResponseInit | undefined): Response | Promise<Response>', gave the following error.
    Argument of type 'number' is not assignable to parameter of type 'string | Promise<string>'.ts(2769)

Thanks for the review, I'm not sure if there's a case I'm not considering here.

The author should do the following, if applicable

• Add tests
• Run tests
• bun run format:fix && bun run lint:fix to format the code
• Add TSDoc/JSDoc to document the code

[yusukebe]

@rossrobino Thank you for the PR.

@usualoma Can you review this?