Capitalize upper cases format characters

[TLINDEN]

fmt.Println(`strf("%d%m") => `, lo.Capitalize(`strf("%d%m")`))

prints:

strf("%d%m") =>  Strf("%D%M")

It upper cases the first char as expected but also all the characters preceded by a %.

[yhuikzdtguioaert]

Had a look at this. The root cause is that Capitalize runs the whole string through a title caser, which upper-cases the first letter of every word segment — so anything following a %, space or punctuation gets capitalized too (e.g. hello world -> Hello World, 123abc -> 123Abc). Per the doc comment it should only upper-case the very first character and lower-case the remainder, matching lodash's capitalize.

I've got a small fix that title-cases just the first rune and lower-cases the rest, keeping the language-aware behaviour (CapitalizeWithLanguage, Turkish etc.) intact. Will send a PR shortly.