'exec fd' considered an error

[danielshahaf]

• exec 2>&1 highlights the 2>& as unknown-token [fixed by 73ee7c1]
• exec {myfd}>myfile highlights {myfd} as unknown-token

Both are valid syntaxes.

[danielshahaf]

The ${(z)} splitter splits 2>&1 as 2>& and 1, but splits {foo}>&1 as {foo}, >&, 1.

{foo} as a single token could also occur directly (echo {foo} works, so long as the { is not a word by itself) or via brace expansion (echo foo{1..42}).

[danielshahaf]

Fixed in 6539f0d