perf(builtin): faster list extend for find_files

[kylo252]

Description

replace table.insert with direct indexing for performance gainz

Type of change

Performance

How Has This Been Tested?

still works :)

Checklist:

• My code follows the style guidelines of this project (stylua)
• I have performed a self-review of my own code

[Conni2461]

did you ever benchmark table.insert vs tbl[#tbl + 1] vs idx = idx + 1; tbl[idx]?

Its one of these placebo things, there is no difference within a margin of error. Try it with plenary.benchmark.

Its also startup code, its not running in a loop. But whatever

Thanks :)