doc/go1.14: add missing slashes

This saves a redirect and makes the document more consistent.

Change-Id: I67840f5dc05dffd8893a055618eb202b682a0ebc
Reviewed-on: https://go-review.googlesource.com/c/go/+/217698
Reviewed-by: Ian Lance Taylor <[email protected]>

Author: toshihiro-shiino

doc/go1.14.html

@@ -436,7 +436,7 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
   in mind.
 </p>
 
-<dl id="hash/maphash"><dt><a href="/pkg/hash/maphash">hash/maphash</a></dt>
+<dl id="hash/maphash"><dt><a href="/pkg/hash/maphash/">hash/maphash</a></dt>
   <dd>
     <p><!-- CL 186877 -->
       This new package provides hash functions on byte sequences.
@@ -626,7 +626,7 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
 
 </dl><!-- math -->
 
-<dl id="math/big"><dt><a href="/pkg/math/big">math/big</a></dt>
+<dl id="math/big"><dt><a href="/pkg/math/big/">math/big</a></dt>
   <dd>
     <p><!-- CL 164972 -->
       The <a href="/pkg/math/big/#Int.GCD"><code>GCD</code></a> method
@@ -759,7 +759,7 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
 
 </dl><!-- runtime -->
 
-<dl id="runtime/pprof"><dt><a href="/pkg/runtime/pprof">runtime/pprof</a></dt>
+<dl id="runtime/pprof"><dt><a href="/pkg/runtime/pprof/">runtime/pprof</a></dt>
   <dd>
     <p><!-- CL 204636, 205097 -->
     The generated profile no longer includes the pseudo-PCs used for inline