tpl/diagrams: Rename Body to Inner

This relates to #9577 – there's no concept a body element in SVG, so we might as well use an exsisting "Hugo term".

tpl/diagrams/diagrams.go

@@ -25,9 +25,17 @@ import (
 )
 
 type SVGDiagram interface {
-	Body() template.HTML
+	// Inner returns the inner markup of the SVG.
+	// This allows for the <svg> container to be created manually.
+	Inner() template.HTML
+
+	// SVG returns the diagram as an SVG, including the <svg> container.
 	SVG() template.HTML
+
+	// Width returns the width of the SVG.
 	Width() int
+
+	// Height returns the height of the SVG.
 	Height() int
 }
 
@@ -35,7 +43,7 @@ type goatDiagram struct {
 	d goat.SVG
 }
 
-func (d goatDiagram) Body() template.HTML {
+func (d goatDiagram) Inner() template.HTML {
 	return template.HTML(d.d.Body)
 }
 

tpl/tplimpl/embedded/templates/_default/_markup/render-codeblock-goat.html

@@ -12,7 +12,7 @@
       {{ else }}
         viewBox="0 0 {{ .Width }} {{ .Height }}"
       {{ end }}>
-      {{ .Body }}
+      {{ .Inner }}
     </svg>
   {{ end }}
 </div>