[deps] Upgrade Docsy to 0.12.0 (#126)

Author: chalin

.htmltest.yml

@@ -1,4 +1,4 @@
-CacheExpires: 9000h # ~ 12 months
+CacheExpires: 13300h # ~ 18 months
 DirectoryPath: public
 TestFilesConcurrently: true
 CheckDoctype: false # Sadly, this is false only because of `static/google*.html`

layouts/_default/_markup/render-heading.html renamed to layouts/_markup/render-heading.html

@@ -1,4 +1,4 @@
-{{ template "_markup/td-render-heading.html" . -}}
+{{ partial "td/render-heading.html" . -}}
 
 {{/* By default, the markdown processor emits a heading on its own line, so we
 don't trim whitespace from the end of this template. */}}