[spec] Remove outdated affiliation

Author: rossberg

document/core/index.bs

@@ -6,7 +6,7 @@ Status: ED
 Level: 2
 TR: https://www.w3.org/TR/wasm-core-2/
 ED: https://webassembly.github.io/spec/core/bikeshed/
-Editor: Andreas Rossberg (Dfinity Stiftung)
+Editor: Andreas Rossberg
 Repository: WebAssembly/spec
 Markup Shorthands: css no, markdown no, algorithm no, idl no
 Abstract: This document describes release 2.0 of the core WebAssembly standard, a safe, portable, low-level code format designed for efficient execution and compact representation.