docs(readme): rewrite

Fix #25

README.md

@@ -23,10 +23,32 @@ errors.Wrap(err, "message")
 ## Don't need traces?
 Call `errors.DisableTrace` or use build tag `noerrtrace`.
 
-## Migration
+## Additional features
+
+### Into
+
+Generic type assertion for errors.
+
+```go
+// Into finds the first error in err's chain that matches target type T, and if so, returns it.
+//
+// Into is type-safe alternative to As.
+func Into[T error](err error) (val T, ok bool)
 ```
-go get github.com/go-faster/errors/cmd/gowrapper@latest
-gowrapper ./...
+
+```go
+if pathError, ok := errors.Into[*os.PathError](err); ok {
+    fmt.Println("Failed at path:", pathError.Path)
+}
+```
+
+### Must
+
+Must is a generic helper, like template.Must, that wraps a call to a function returning (T, error)
+and panics if the error is non-nil.
+
+```go
+func Must[T any](val T, err error) T
 ```
 
 ## License