fixed margin (for full-page)

src/renderer.typ

@@ -449,7 +449,8 @@
     (
       width: auto,
       height: auto,
-      fill: config.background
+      fill: config.background,
+      margin: 0cm
     )
   } else {
     (:)

src/schema.typ

@@ -27,7 +27,7 @@
   let lang = schema.lang
   let content = schema.text
   if not lang in valid-extensions {
-    let fmts = valid-extensions.map(fmt => "." + fmt).join(", ")
+    let fmts = valid-extensions.join(", ")
     fmts = "(" + fmts + ")"
     panic("Unsupported format '" + lang + "'. Valid formats: " + fmts)
   }