Move template guidance underneath

Two problems with having it on the side:
- some users didn’t see it at all
- there wasn’t space to have additional guidance about Markdown-style
  formatting

app/templates/partials/templates/guidance-character-count.html

@@ -1,12 +1,8 @@
-<details>
-  <summary class="button tertiary-button">Message length</summary>
-  <div id="guidance-personalisation">
-    <p>
-      If your message is long then it will
-      cost more.
-    </p>
-    <p>
-      See <a href="{{ url_for('.pricing') }}">pricing</a> for details.
-    </p>
-  </div>
-</details>
+<h2 class="heading-medium">Message length</h2>
+<p>
+  If your message is long then it will
+  cost more.
+</p>
+<p>
+  See <a href="{{ url_for('.pricing') }}">pricing</a> for details.
+</p>

app/templates/partials/templates/guidance-links.html

@@ -1,8 +1,4 @@
-<details>
-  <summary class="button tertiary-button">Links and URLs</summary>
-  <div id="guidance-personalisation">
-    <p>
-      Always use full URLs, starting with https://
-    </p>
-  </div>
-</details>
+<h2 class="heading-medium">Links and URLs</h2>
+<p>
+  Always use full URLs, starting with https://
+</p>

app/templates/partials/templates/guidance-personalisation.html

@@ -1,14 +1,12 @@
-<details>
-  <summary class="button tertiary-button">Personalisation</summary>
-  <div id="guidance-personalisation">
-    <p>
-      Use double brackets to add personalisation.
-    </p>
-    <p>
-      Correct: ((name))
-    </p>
-    <p>
-      Incorrect: ((Helen))
-    </p>
-  </div>
-</details>
+<h2 class="heading-medium">
+  Personalisation
+</h2>
+<p>
+  Use double brackets to add personalisation.
+</p>
+<p>
+  Correct: ((name))
+</p>
+<p>
+  Incorrect: ((Helen))
+</p>

app/templates/views/edit-email-template.html

@@ -26,8 +26,7 @@
             delete_link_text='Delete this template'
           ) }}
         </div>
-        <aside class="column-one-third">
-          <h2 style="margin: 0 0 5px 0;">Help</h2>
+        <aside class="column-whole">
           {% include "partials/templates/guidance-personalisation.html" %}
           {% include "partials/templates/guidance-links.html" %}
         </aside>

app/templates/views/edit-sms-template.html

@@ -25,8 +25,7 @@
             delete_link_text='Delete this template'
           ) }}
         </div>
-        <aside class="column-one-third">
-          <h2 style="margin: 0 0 5px 0;">Help</h2>
+        <aside class="column-whole">
           {% include "partials/templates/guidance-personalisation.html" %}
           {% include "partials/templates/guidance-links.html" %}
           {% include "partials/templates/guidance-character-count.html" %}