We need to add version.diff.dictionary_words credibility signal so that consumers can know the difference in terms of dictionary words between the current revision as compared to its parent revision.

The implementation will require a small schema addition and making calls to utilities to populate the field values.

Steps:

• Step 1: First, need to update the version schema . [pls refer to documentation repo JSON schema/diff.json and delta.json]

{
  "identifier": 1063955750,
   .
   .
   "diff" : {
        "dictionary_words" : {
            "increase": 11,             
            "decrease": 2,
             "sum"      : 9,
             "proportional_increase" : 2,
              "proportional_decrease" : -2.3333         
              }
           }
}

• Step:2 Get the revision data with the two wikitexts (current rev and parent rev) in the articleupdate handler using revision utilitiy.

• Step:3 Get the word tokens in the two wikitexts using this utilitiy.

• Step:4 Get the dictionary words in the two wikitexts using this utilitiy.

• Step:5 Populate the required fields using utilities (increase, decrease, sum, proportional_increase, and proportional_decrease)