[MM-37755] Idiomatic naming (SMTP, TLS, TCP, XML, CSS, HTML, HTTP) (#18103)

api4/user.go

@@ -1845,7 +1845,7 @@ func login(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	c.LogAuditWithUserId(user.Id, "success")
 
-	if r.Header.Get(model.HeaderRequestedWith) == model.HeaderRequestedWithXml {
+	if r.Header.Get(model.HeaderRequestedWith) == model.HeaderRequestedWithXML {
 		c.App.AttachSessionCookies(c.AppContext, w, r)
 	}