Rewrite warning about VTL removal in 2.16 release notes

- Support for Soy was introduced in 2.14, not 2.15.

- Add link to the 2.14 release notes.

- Expand on where the template files are located.

Change-Id: Ie95b5067255c2540c36b9f0aedf0c71b886ac14e
diff --git a/releases/2.16.md b/releases/2.16.md
index 0a94e25..9361ef7 100644
--- a/releases/2.16.md
+++ b/releases/2.16.md
@@ -34,12 +34,12 @@
 
 ### Support for Velocity templates removed
 
-In version 2.15 support for Soy templates was added. For backwards compatibility
-support for Velocity templates (VTL) was kept.
+In [version 2.14](2.14.md) support for Soy templates was added. For backwards
+compatibility, support for Velocity templates (VTL) was kept.
 
 In version 2.16 support for VTL is completely removed. Site administrators must
-replace any Velocity templates (*.vm) with the equivalent Soy templates before
-upgrading to this version.
+replace any Velocity templates (`.vm` files in `$site/etc/mail/`) with the equivalent
+Soy templates before upgrading to this version.
 
 ## New Features