Split F# and OCaml entries (#475)

While they use the same mode, OCaml is easy to miss.

lib/constants.js

@@ -219,7 +219,7 @@ export const LANGUAGES = [
     mode: 'fortran'
   },
   {
-    name: 'F# / OCaml',
+    name: 'F#',
     mode: 'mllike'
   },
   {
@@ -328,6 +328,10 @@ export const LANGUAGES = [
     mime: 'text/x-objectivec',
     short: 'objectivec'
   },
+  {
+    name: 'OCaml',
+    mode: 'mllike'
+  },
   {
     name: 'Pascal',
     mode: 'pascal'