Order rules in quote_token! and quote_token_spanned! by frequency.

[nnethercote]

This reduces cargo check times by 4-9% on a few crates that use
quote! heavily.

[nnethercote]

Here are some cargo-check measurements done with the harness from rustc-perf and six crates known to use quote! heavily.

Benchmark & Profile	Scenario	% Change	Significance Factor?
pest_generator-2.1.3 check	incr-unchanged	-9.59%	47.97x
num-derive-0.3.3 check	incr-unchanged	-9.31%	46.55x
futures-macro-0.3.19 check	incr-unchanged	-7.71%	38.56x
mockall_derive-0.11.0 check	incr-unchanged	-7.69%	38.45x
pest_generator-2.1.3 check	full	-5.88%	29.42x
num-derive-0.3.3 check	full	-5.63%	28.14x
pest_generator-2.1.3 check	incr-full	-5.34%	26.68x
num-derive-0.3.3 check	incr-full	-5.24%	26.20x
futures-macro-0.3.19 check	full	-4.64%	23.18x
mockall_derive-0.11.0 check	full	-4.31%	21.54x
futures-macro-0.3.19 check	incr-full	-4.05%	20.24x
mockall_derive-0.11.0 check	incr-full	-3.90%	19.48x
scroll_derive-0.11.0 check	incr-full	-0.00%	0.01x
scroll_derive-0.11.0 check	full	0.00%	0.01x
ctor-0.1.21 check	full	-0.00%	0.00x
ctor-0.1.21 check	incr-unchanged	-0.00%	0.00x
ctor-0.1.21 check	incr-full	-0.00%	0.00x
scroll_derive-0.11.0 check	incr-unchanged	-0.00%	0.00x

[dtolnay]

Thanks!

Would swapping the two token arguments of quote_token! help? Naïvely it seems like matching immediately on the first token, instead of parsing an ident in every rule before matching on the second token, might be quicker.

[nnethercote]

Would swapping the two token arguments of quote_token! help?

Quite possibly. I'll try it tomorrow, and likewise for the macros above quote_token!.

[lqd]

I was curious and tried David's suggestion: it does indeed improve things a tiny bit.

Benchmark & Profile	Scenario	% Change	Significance Factor ?
pest_generator-2.1.3 check	incr-unchanged	-2.18%	10.91x
num-derive-0.3.3 check	incr-unchanged	-2.05%	10.26x
mockall_derive-0.11.0 check	incr-unchanged	-1.79%	8.97x
pest_generator-2.1.3 check	full	-1.34%	6.69x
num-derive-0.3.3 check	full	-1.21%	6.06x
pest_generator-2.1.3 check	incr-full	-1.18%	5.90x
futures-macro-0.3.19 check	incr-unchanged	-1.17%	5.86x
num-derive-0.3.3 check	incr-full	-1.09%	5.47x
mockall_derive-0.11.0 check	full	-1.00%	5.00x
mockall_derive-0.11.0 check	incr-full	-0.88%	4.39x
futures-macro-0.3.19 check	full	-0.71%	3.57x
futures-macro-0.3.19 check	incr-full	-0.61%	3.06x

I'll open a PR shortly.