Fix fit-content in Firefox

Author: ai

data/prefixes.js

@@ -411,7 +411,7 @@ let sizeProps = [
 ]
 
 f(intrinsic, browsers =>
-  prefix(['max-content', 'min-content', 'fit-content'], {
+  prefix(['max-content', 'min-content'], {
     props: sizeProps,
     feature: 'intrinsic-width',
     browsers
@@ -426,6 +426,14 @@ f(intrinsic, { match: /x|\s#4/ }, browsers =>
   })
 )
 
+f(intrinsic, { match: /x|\s#5/ }, browsers =>
+  prefix(['fit-content'], {
+    props: sizeProps,
+    feature: 'intrinsic-width',
+    browsers
+  })
+)
+
 // Zoom cursors
 f(require('caniuse-lite/data/features/css3-cursors-newer'), browsers =>
   prefix(['zoom-in', 'zoom-out'], {