Bug: NotFound handler was called although route exists

[sknr]

💡 The feature or bug you are proposing

Bugfix: #97

📄 The description of the bug or the logic behind your proposal

If the route exists but the handler is missing, I got a HTTP 404 Not Found error.

🚀 The expected result

If the route exists but the handler is missing, I expect to see a 405 Method Not Allowed error.

Example

r := bunrouter.New()
r.POST("/city/:city/postalcode/:postal", exampleHandler)

Assume that the records exists:
Make a GET request to /city/1/postalcode/1 and you get a 404 instead of a 405 error.