fix: adds mention that errata has been applied

Co-authored-by: Vladimír Gorej <[email protected]>

Author: baywet

src/oas.md

@@ -580,7 +580,7 @@ ucschar        =  %xA0-D7FF / %xF900-FDCF / %xFDF0-FFEF
 iprivate       =  %xE000-F8FF / %xF0000-FFFFD / %x100000-10FFFD
 ```
 
-Here, `literals`, `pct-encoded`, `uschar` and `iprivate` definitions are taken from [RFC 6570](https://www.rfc-editor.org/rfc/rfc6570).
+Here, `literals`, `pct-encoded`, `ucschar` and `iprivate` definitions are taken from [RFC 6570](https://www.rfc-editor.org/rfc/rfc6570), incorporating the corrections specified in [Errata 6937](https://www.rfc-editor.org/errata/eid6937) for `literals`.
 
 ##### Fixed Fields