syntax: make quoteState 32 bits
syntax: make quoteState 32 bits

Slight performance win, like when we made token 32 bits.

name                   old time/op    new time/op    delta
Parse/LongStrs-4         5.24µs ± 2%    5.24µs ± 0%    ~     (p=0.657 n=6+4)
Parse/Cmds+Nested-4      7.01µs ± 1%    7.06µs ± 0%  +0.70%  (p=0.030 n=6+5)
Parse/Vars+Clauses-4     5.71µs ± 1%    5.66µs ± 0%  -0.95%  (p=0.030 n=6+5)
Parse/Binary+Redirs-4    6.51µs ± 1%    6.44µs ± 1%  -1.07%  (p=0.017 n=6+6)

mvdan/sh,mvdan/sh,mvdan/sh,mvdan/sh