Add substituteHoverableAtRules, previously accidentally ignored

src/lib/substituteHoverableAtRules.js

@@ -0,0 +1,27 @@
+import _ from 'lodash'
+import postcss from 'postcss'
+import cloneNodes from '../util/cloneNodes'
+
+export default function(options) {
+  return function(css) {
+    css.walkAtRules('hoverable', atRule => {
+
+      atRule.walkRules(rule => {
+        // Might be wise to error if the rule has multiple selectors,
+        // or weird compound selectors like .bg-blue>p>h1
+        rule.selectors =  [
+          rule.selector,
+          `.\\@${rule.selector.slice(1)}:hover`,
+          `.\\@${rule.selector.slice(1)}:focus`
+        ]
+      })
+
+      const nodes = atRule.nodes
+      const rules =  cloneNodes(nodes)
+
+      atRule.parent.insertBefore(atRule, nodes)
+
+      atRule.remove()
+    })
+  }
+}