doc/go1.15: update Go 1.15 release notes using relnote

The additions were generated using golang.org/x/build/cmd/relnote.

Updates #37419

Change-Id: I99e934377e4bb511c44908039ad6d3bfd3ee35ce
Reviewed-on: https://go-review.googlesource.com/c/go/+/241065
Run-TryBot: Carlos Amedee <carlos@golang.org>
Reviewed-by: Alexander Rakoczy <alex@golang.org>
Reviewed-by: Andrew Bonventre <andybons@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/doc/go1.15.html b/doc/go1.15.html
index 0d185de..45ffec4 100644
--- a/doc/go1.15.html
+++ b/doc/go1.15.html
@@ -335,6 +335,11 @@
   improvements expected in future releases.
 </p>
 
+<p><!-- CL 207877 -->
+  TODO: <a href="https://golang.org/cl/207877">https://golang.org/cl/207877</a>: Revert -buildmode=pie to internal linking.
+  The linker defaults to internal linking mode for PIE on linux/amd64 and linux/arm64, which does require a C linker.
+</p>
+
 <h2 id="objdump">Objdump</h2>
 
 <p><!-- CL 225459 -->
@@ -938,6 +943,10 @@
        return temporary directories that are automatically cleaned up
        at the end of the test.
     </p>
+
+    <p><!-- CL 229085 -->
+      TODO: <a href="https://golang.org/cl/229085">https://golang.org/cl/229085</a>: reformat test chatty output
+    </p>
   </dd>
 </dl><!-- testing -->