doc/go1.14: -d=checkptr is not yet recommended on Windows

Hopefully we'll have the remaining safety violations in the standard
library ironed out by 1.15.

We also fix a minor (but important) typo while we're here.

Updates #34964, #34972.

Change-Id: Ic72fd4d9411b749f8c0cea87e95ab68347009893
Reviewed-on: https://go-review.googlesource.com/c/go/+/214118Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

doc/go1.14.html

@@ -301,9 +301,9 @@ TODO
   This release adds <code>-d=checkptr</code> as a compile-time option
   for adding instrumentation to check that Go code is following
   <code>unsafe.Pointer</code> safety rules dynamically.
-  This option is enabled by default with the <code>-race</code>
-  or <code>-msan</code> flags, and can be disabled
-  with <code>-gcflags=-all=-d=checkptr=0</code>.
+  This option is enabled by default (except on Windows) with
+  the <code>-race</code> or <code>-msan</code> flags, and can be
+  disabled with <code>-gcflags=all=-d=checkptr=0</code>.
   Specifically, <code>-d=checkptr</code> checks the following:
 </p>
 
@@ -320,6 +320,11 @@ TODO
   </li>
 </ol>
 
+<p>
+  Using <code>-d=checkptr</code> is not currently recommended on
+  Windows because it causes false alerts in the standard library.
+</p>
+
 <p><!-- CL 204338 -->
   The compiler can now emit machine-readable logs of key optimizations
   using the <code>-json</code> flag, including inlining, escape