quickfix: replace manual slicing with `strings.HasPrefix`

[ccoVeille]

I faced to following piece of advice in recent code review

Please consider the following pseudocode

func foo(path string) {
    if path[0] == '/' { // here we are checking if first character is a slash
        // whatever
    }
    
    // ...
}

foo("/path/foo/bar)
foo("path/foo/bar)

The following code should be preferred and suggested

func foo(path string) {
    if strings.HasPrefix(path, "/") {
        // whatever
    }
    
    // ...
}

foo("/path/bar")
foo("path/bar")

This rule someone completes S1017

The pattern is very common:

• https://github.com/search?q=lang%3Ago+%22%5B0%5D+%3D%3D+%27%22&type=code
• https://github.com/search?q=lang%3Ago+%22%5B0%5D+%21%3D+%27%22&type=code

[ccoVeille]

The opposite may also be detected

func foo(path string) {
    if path[len(path)-1] == '/' { // here we are checking if last character is a slash
        // whatever
    }
    
    // ...
}

foo("/path/bar/")
foo("/path/bar")

func foo(path string) {
    if strings.HasSuffix(path, "/") {
        // whatever
    }
    
    // ...
}

[ccoVeille]

patterns like this could also be detected, with the same checker maybe

	path := "foo"

	if path[0:2] == "fo" {
		// whatever
	}

	// 

This pattern is pretty common https://github.com/search?q=lang%3Ago+%22%5B0%3A2%5D+%3D%3D%22&type=code https://github.com/search?q=lang%3Ago+%22%5B0%3A2%5D+%21%3D%22&type=code

example https://github.com/grafana/k6/blob/93649df0939a4cb89828da2be40c98100e92fab1/lib/archive.go#L161