issue lvl: low; `-Werror -Wsign-conversion` = build error

[CharaVerKys]

there just a little of them (today its total 7)
maybe just silence this errors with explicit cast?

samples:
get_indent_level() * style.indent_size, ' '); int->uint
std::vector<std::size_t> order_index(std::distance(b, e)); long->ulong
const parser & pa = **(b + i); ulong->long
...
like, to static_cast<unsigned int>(get_indent_level()) and std::vector<std::size_t> order_index( static_cast<std::size_t>(std::distance(b, e)) );
...
if ill change it in non-single file version, and pull request, will it be accepted, or no one care about signs?

[grafikrobot]

I do some warnings tests. So this would be another warning that didn't get caught by the regular flags. :-( So, yes, if I get a PR, I'll merge it.

[CharaVerKys]

forgot about tihs issue, 3 days pass...
idk how to properly set test for this, so dont touch test dir
clang++ -v => 21.1.6
clang++ -Wall -Wpedantic -Wconversion -Wextra test.cpp -I./include
test just include lyra header and empty main
#109