perf(rome_js_formatter): Reduce FormatElement size

[MichaReiser]

This PR reduces the size of a FormatElement from 56 to 32 bytes by:

• Using a Box<str> to store a dynamic token's string as it doesn't need to be mutable (safes 8 bytes for the capacity)
• Only storing the start position for a DynamicToken because the length isn't used by the printer
• Change the semantics of verbatim_ranges to store the ranges in the formatted string. The ranges in the formatted output should be sufficient for debugging and it allows to resolve the String rather than having to store it on the FormatElement (range can be computed in the printer).

It further improves the get_lines_between implementation to only check the leading trivia because the trailing trivia should never contain new lines except for the EOF token which isn't relevant for that function.

This improves the formatter's performance by about 10%

group                                    format-element                         main
-----                                    --------------                         ----
formatter/checker.ts                     1.00    250.2±5.03ms    10.4 MB/sec    1.12    280.3±3.07ms     9.3 MB/sec
formatter/compiler.js                    1.00    145.6±1.30ms     7.2 MB/sec    1.09    158.7±1.82ms     6.6 MB/sec
formatter/d3.min.js                      1.00    117.4±3.70ms     2.2 MB/sec    1.11    129.9±1.57ms     2.0 MB/sec
formatter/dojo.js                        1.00      7.4±0.15ms     9.2 MB/sec    1.09      8.1±0.02ms     8.4 MB/sec
formatter/ios.d.ts                       1.00    181.2±1.95ms    10.3 MB/sec    1.18   214.0±18.85ms     8.7 MB/sec
formatter/jquery.min.js                  1.00     29.1±0.55ms     2.8 MB/sec    1.10     32.1±0.23ms     2.6 MB/sec
formatter/math.js                        1.00    233.1±4.69ms     2.8 MB/sec    1.12    261.7±1.85ms     2.5 MB/sec
formatter/parser.ts                      1.00      5.3±0.15ms     9.2 MB/sec    1.08      5.7±0.05ms     8.5 MB/sec
formatter/pixi.min.js                    1.00    131.0±7.11ms     3.3 MB/sec    1.09    142.6±2.03ms     3.1 MB/sec
formatter/react-dom.production.min.js    1.00     37.0±0.82ms     3.1 MB/sec    1.07     39.5±0.59ms     2.9 MB/sec
formatter/react.production.min.js        1.00  1825.1±57.85µs     3.4 MB/sec    1.08   1970.9±3.55µs     3.1 MB/sec
formatter/router.ts                      1.00      3.7±0.09ms    16.2 MB/sec    1.09      4.0±0.11ms    14.8 MB/sec
formatter/tex-chtml-full.js              1.00    288.3±5.19ms     3.2 MB/sec    1.10    316.9±3.00ms     2.9 MB/sec
formatter/three.min.js                   1.00    155.7±3.79ms     3.8 MB/sec    1.08    167.6±3.41ms     3.5 MB/sec
formatter/typescript.js                  1.00    945.2±6.64ms    10.1 MB/sec    1.10   1037.9±8.11ms     9.2 MB/sec
formatter/vue.global.prod.js             1.00     49.1±1.49ms     2.5 MB/sec    1.05     51.8±1.26ms     2.3 MB/sec

Test Plan

cargo test.

I changed a node implementation to call format_verbatim and verified the printed text & ranges.

Future improvements

It should be possible to bring the FormatElement size down to 24 bytes by

• Introducing a new Marker Element that creates a source map entry from source position to formatted position
• Extract the source position from the Token variants
• Replace the List's Vec with a Vec that uses u32 for indices. This should be sufficient, considering that Rome only supports files with less than u32::max characters

[github-actions]

Parser conformance results on ubuntu-latest

js/262

Test result	main count	This PR count	Difference
Total	45323	45323	0
Passed	44383	44383	0
Failed	940	940	0
Panics	0	0	0
Coverage	97.93%	97.93%	0.00%

jsx/babel

Test result	main count	This PR count	Difference
Total	39	39	0
Passed	36	36	0
Failed	3	3	0
Panics	0	0	0
Coverage	92.31%	92.31%	0.00%

ts/babel

Test result	main count	This PR count	Difference
Total	588	588	0
Passed	519	519	0
Failed	69	69	0
Panics	0	0	0
Coverage	88.27%	88.27%	0.00%

ts/microsoft

Test result	main count	This PR count	Difference
Total	16171	16171	0
Passed	12315	12315	0
Failed	3856	3856	0
Panics	0	0	0
Coverage	76.15%	76.15%	0.00%

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[github-actions]

Playground for commit ce407cc

[ematipico]

Any particular reason why we removed this function? It was there mainly to be in line with into_sourcemap and into_code. If it's been removed because not used, then we should do the same with into_sourcemap too.

[MichaReiser]

I removed it because it wasn't used and the struct no longer stores the Vec that it could just take and return. Having the iterator specific method makes it clear that taking the verbatim sources requires a vector allocation.