checker: fix veb route method param with non ctx name (fix #23105)

[yuyi98]

This PR fix veb route method param with non ctx name (fix #23105).

• Fix veb route method param with non ctx name.
• Add test.

import veb

pub struct User {
pub mut:
	name string
	id   int
}

// Our context struct must embed `veb.Context`!
pub struct Context {
	veb.Context
pub mut:
	// In the context struct we store data that could be different
	// for each request. Like a User struct or a session id
	user       User
	session_id string
}

pub struct App {
pub:
	// In the app struct we store data that should be accessible by all endpoints.
	// For example, a database or configuration values.
	secret_key string
}

// This is how endpoints are defined in veb. This is the index route
pub fn (app &App) index(mut context Context) veb.Result {
	return context.text('Hello V! The secret key is "${app.secret_key}"')
}

fn main() {
	mut app := &App{
		secret_key: 'secret'
	}
	// Pass the App and context type and start the web server on port 8080
	veb.run[App, Context](mut app, 8080)
}

PS D:\Test\v\tt1> v run .
[veb] Running app on http://localhost:8080/

_{Huly®: V_0.6-21544}

[spytheman]

Excellent work.

[spytheman]

@medvednikov ... that veb.Context implicit handling in the compiler, is a very big hack, and I suspect that it will continue to trip users :-| .

A big reason for veb instead of vweb, was to minimize the amount of special cases for its support in the compiler, in favor of using general features, supported for all user code :-( ...