Use automatic TOC anchors

wiki/src/contribute/how/documentation/release_notes/template.mdwn

@@ -20,9 +20,9 @@ vulnerabilities|security/Numerous_security_holes_in_$VERSION-1]]. You should upg
 
 [[!toc levels=1]]
 
-# New features
+<h1 id="features">New features</h1>
 
-# Changes and updates
+<h1 id="changes">Changes and updates</h1>
 
 <-- You can reuse the following subsections if the section gets too big:
 
@@ -46,13 +46,11 @@ Wi-Fi, etc.):
 
 -->
 
-# Fixed problems
+<h1 id="fixes">Fixed problems</h1>
 
 For more details, read our [[!tails_gitweb debian/changelog desc="changelog"]].
 
-<a id="known-issues"></a>
-
-# Known issues
+<h1 id="issues">Known issues</h1>
 
 <!--
 
@@ -65,7 +63,7 @@ None specific to this release.
 
 See the list of [[long-standing issues|support/known_issues]].
 
-# Get Tails $VERSION
+<h1 id="get">Get Tails $VERSION</h1>
 
 ## To upgrade your Tails USB stick and keep your persistent storage
 
@@ -93,7 +91,7 @@ Tails $VERSION directly:
   - [[For USB sticks (USB image)|install/download]]
   - [[For DVDs and virtual machines (ISO image)|install/download-iso]]
 
-# What's coming up?
+<h1 id="next">What's coming up?</h1>
 
 Tails $VERSION+1 is [[scheduled|contribute/calendar]] for $MONTH $DAY.