[release-branch.go1.4] doc/go1.4.html: rewrite first sentence to make it clearer

««« CL 178910043 / 3916b070c5f3
doc/go1.4.html: rewrite first sentence to make it clearer
The grammar was atrocious, probably the victim of an editing error.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://codereview.appspot.com/178910043
»»»

LGTM=r
R=r
CC=golang-codereviews
https://codereview.appspot.com/175310043