doc: remove space in "Go 1. 8"

And reflow paragraph while I'm at it.

Change-Id: Ia13bb364783790fbd9f8b69ef268f8a4b71679cb
Reviewed-on: https://go-review.googlesource.com/33767Reviewed-by: Chris Broadfoot <cbro@golang.org>

doc/go1.8.html

@@ -44,8 +44,9 @@ and <a href="#sort_slice">simplifies sorting slices</a>.
 <h2 id="language">Changes to the language</h2>
 
 <p>
-  When explicitly converting a value from one struct type to another, as of Go 1. 8 the tags are ignored.
-  Thus two structs that differ only in their tags may be converted from one to the other:
+  When explicitly converting a value from one struct type to another,
+  as of Go 1.8 the tags are ignored. Thus two structs that differ
+  only in their tags may be converted from one to the other:
 </p>
 
 <pre>