fix(http1): fix title-case option when header names have symbols
fix(http1): fix title-case option when header names have symbols

Don't eat the first character in a header name if it's not a letter. Same thing after a `-`
hyperium/hyper,yazaddaruvala/hyper,tshepang/hyper,tshepang/hyper,hyperium/hyper,tshepang/hyper,hyperium/hyper,yazaddaruvala/hyper