doc/go1.10: fix HTML close tags

Change-Id: I28ddb8cd347120c08d5b58ae20f481b60416abc1
Reviewed-on: https://go-review.googlesource.com/82755Reviewed-by: Andrew Bonventre <andybons@golang.org>

doc/go1.10.html

@@ -1042,11 +1042,11 @@ compute square roots.
 <dd>
 <p>
 Branch cuts and other boundary cases in
-<a href="/pkg/math/cmplx/#Asin"><code>Asin<code></a>,
-<a href="/pkg/math/cmplx/#Asinh"><code>Asinh<code></a>,
-<a href="/pkg/math/cmplx/#Atan"><code>Atan<code></a>,
+<a href="/pkg/math/cmplx/#Asin"><code>Asin</code></a>,
+<a href="/pkg/math/cmplx/#Asinh"><code>Asinh</code></a>,
+<a href="/pkg/math/cmplx/#Atan"><code>Atan</code></a>,
 and
-<a href="/pkg/math/cmplx/#Sqrt"><code>Sqrt<code></a>
+<a href="/pkg/math/cmplx/#Sqrt"><code>Sqrt</code></a>
 have been corrected to match the definitions used in the C99 standard.
 </p>
 </dl>