Returns true if there exists a doc comment between the start
of token start_token and the start of token end_token.
fn hasDocComment(tree: Ast, start_token: Ast.TokenIndex, end_token: Ast.TokenIndex) bool
fn hasDocComment(tree: Ast, start_token: Ast.TokenIndex, end_token: Ast.TokenIndex) bool {
return std.mem.indexOfScalar(
Token.Tag,
tree.tokens.items(.tag)[start_token..end_token],
.doc_comment,
) != null;
}