migrate to rslib -> tsdown

[ryoppippi]

build result:

rslib

~/g/g/t/node-vimhelp master ❱ hyperfine -w 1 -r 5 'npm run build'
Benchmark 1: npm run build
  Time (mean ± σ):      1.449 s ±  0.008 s    [User: 2.790 s, System: 0.324 s]
  Range (min … max):    1.442 s …  1.460 s    5 runs

tsdown

~/g/g/t/node-vimhelp tsdown 16.5s ❱ hyperfine -w 1 -r 5 'npm run build'
Benchmark 1: npm run build
  Time (mean ± σ):     490.5 ms ±   5.4 ms    [User: 520.5 ms, System: 137.3 ms]
  Range (min … max):   484.1 ms … 496.0 ms    5 runs

for refernce
tsdown without publint and unused

~/g/g/t/node-vimhelp tsdown• ↓1 ❱ hyperfine -w 1 -r 5 'npm run build'
Benchmark 1: npm run build
  Time (mean ± σ):     253.3 ms ±   3.1 ms    [User: 274.1 ms, System: 75.5 ms]
  Range (min … max):   250.0 ms … 256.8 ms    5 runs

[codecov-commenter]

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[ryoppippi]

because we include sourcemap, why don't we ship src dir

[thinca]

よくわからんがたぶんヨシ！