Dynamic buffer size

[sidp]

This PR implements dynamic sizing of the buffer used by tree-sitter, to fix #74 . The default 32 KB buffer size is maintained, but any files over that size will be parsed with a dynamic buffer size matching the file size + 32 bytes of padding instead.

I suggest that a warning is logged for files where the size starts to noticeably affect performance. It's currently set to 2 MB but I'm of course open to suggestions to change it. Logging for every file is over 32 kb might get noisy in some codebases.

Here are some performance metrics captured on my Macbook Pro M1:

file size	parse time
1 kb	10 ms
100 kb	145 ms
1 mb	1656 ms
2 mb	3849 ms
3 mb	6487 ms
4 mb	11278 ms
5 mb	13039 ms
10 mb	40163 ms

[erikyo]

@sidp, I have to thank you again! ☺️

Your contributions have been really valuable!

[sidp]

No problem at all! 🙌