protected Collection<PsiReference> createPrefixReferences(@NotNull ASTNode startTagName,
                                                            @NotNull String prefix,
                                                            @Nullable TagNameReference tagRef) {
    return Collections.singleton(new SchemaPrefixReference(
      myTag, TextRange.from(startTagName.getStartOffset() - myTag.getNode().getStartOffset(), prefix.length()), prefix, tagRef));
  }
protected Collection<PsiReference> createPrefixReferences(@NotNull ASTNode startTagName,
                                                            @NotNull String prefix,
                                                            @Nullable TagNameReference tagRef)