remove ExprIndStr

it can be replaced with StringToken if we add another bit if information to
StringToken, namely whether this string should take part in indentation scanning
or not. since all escaping terminates indentation scanning we need to set this
bit only for the non-escaped IND_STRING rule.

this improves performance by about 1%.

 before

  nix search --no-eval-cache --offline ../nixpkgs hello
    Time (mean ± σ):      8.880 s ±  0.048 s    [User: 6.809 s, System: 1.643 s]
    Range (min … max):    8.781 s …  8.993 s    20 runs

  nix eval -f ../nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix
    Time (mean ± σ):     375.0 ms ±   2.2 ms    [User: 339.8 ms, System: 35.2 ms]
    Range (min … max):   371.5 ms … 379.3 ms    20 runs

  nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
    Time (mean ± σ):      2.831 s ±  0.040 s    [User: 2.536 s, System: 0.225 s]
    Range (min … max):    2.769 s …  2.912 s    20 runs

 after

  nix search --no-eval-cache --offline ../nixpkgs hello
    Time (mean ± σ):      8.832 s ±  0.048 s    [User: 6.757 s, System: 1.657 s]
    Range (min … max):    8.743 s …  8.921 s    20 runs

  nix eval -f ../nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix
    Time (mean ± σ):     367.4 ms ±   3.2 ms    [User: 332.7 ms, System: 34.7 ms]
    Range (min … max):   364.6 ms … 374.6 ms    20 runs

  nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
    Time (mean ± σ):      2.810 s ±  0.030 s    [User: 2.517 s, System: 0.225 s]
    Range (min … max):    2.742 s …  2.854 s    20 runs

0 files changed, 0 insertions, 0 deletions