bpaf_derive: use trim_start in doc_comment parser?

[bzm3r]

We have at the moment:

bpaf/bpaf_derive/src/utils.rs

Lines 68 to 70 in 49b7127

	if s.starts_with(' ') {
	s = s[1..].to_string();
	}

Should this just be replaced with a call to trim_start?

(I am happy to implement this, if it makes sense.)

[pacak]

This part preprocesses the comment block changing it from

/// xxx
/// yyyy

giving you back "xxx" and "yyy".

But this preserves spaces past the first one so /// xxx is " xxx". The intention is that a single space is used to format doc comments normally while more spaces are used for more format options - extra single space lets you to force a line break, etc. I'm pretty sure I have this behavior documented somewhere but I can't find it...

I guess we can use strip_prefix to remove that single space and make the behavior clearer in the documentation.... Feel free to do the strip_prefix change, as for the documentation - I have something in work already, it's just needs to be split into smaller chunks, cleaned up and merged... If you want to help here - that would be great.