Command substitutions with nested parentheses are not escaped correctly

[steinybot]

Description

Command substitutions that contains nested parentheses (e.g. with a nested parameter expansion containing a flag) are not escaped correctly.

Versions

Component	Version
Zsh Escape	a04551a (git rev-parse HEAD)
OS	Windows 10
Zsh	zsh 5.5.1 (i686-pc-cygwin) (zsh --version)

Steps To Reproduce

Steps to reproduce the bug:

1. Use the following file bad-script.zsh:

foo=$(print ${(qq)bar})

2. Run:

zsh-escape.zsh fix bad-script.zsh

Expected Behaviour

foo="$(print ${(qq)bar})"

Actual Behaviour

foo="$(print ${(qq)"bar})