add: figure plugin

prepends/figure.typ

@@ -0,0 +1,15 @@
+#show figure: it => {
+  if it.body.func() == image {
+    let src = it.body.source
+    let dot-pos = src.rev().position(".")
+    let full-src = if dot-pos != none {
+      src.slice(0, src.len() - dot-pos - 1) + "_full" + src.slice(src.len() - dot-pos - 1)
+    } else {
+      src + "_full"
+    }
+    show image: img => link(full-src, img)
+    it
+  } else {
+    it
+  }
+}