--assert-ok accepts 3xx, but --help and README both say 2xx

[korya]

Problem

AssertStatusOK (assertions.go:12) treats 200–399 as OK:

if s := res.StatusCode; s < 200 || s >= 400 {

But the flag help says Assert response is successful (2xx) and the README table says Assert 2xx status code.

Reproduction

$ http-assert --assert-ok http://127.0.0.1:8791/redirect   # responds 302 Found
[.] HTTP/1.1 GET http://127.0.0.1:8791/redirect
[:] HTTP/1.1 302 Found
[+] PASSED
[exit=0]

This is a docs bug, not a logic bug

assertions_test.go (Test_AssertStatusOK) explicitly pins 300, 301, 307 and 399 as OK, so the 2xx–3xx range is intentional (curl -f semantics). Only the documentation is wrong.

Why it matters

Combined with redirects not being followed, a health check pointed at an endpoint that starts 302-ing to a login page passes green.

Suggested fix

• Update the flag description to something like Assert response is not an error (2xx or 3xx).
• Update the README assertion table.
• Consider a separate --assert-2xx for people who want the strict reading.