Readability improvement for activity score (#398)

Author: Michadelic

patterns/2-structured/repository-activity-score.md

@@ -71,7 +71,7 @@ function calculateScore(repo) {
     repo._InnerSourceMetadata = repo._InnerSourceMetadata || {};
     if (repo._InnerSourceMetadata.participation) {
         // average commits: adds a bonus multiplier between 0..1 to overall score (1 = >10 commits per week, 0 = less than 3 commits per week)
-        let iAverageCommitsPerWeek = repo._InnerSourceMetadata.participation.slice(repo._InnerSourceMetadata.participation.length - 13).reduce((a, b) => a + b) / 13;
+        let iAverageCommitsPerWeek = repo._InnerSourceMetadata.participation.slice(-13).reduce((a, b) => a + b) / 13;
         iScore = iScore * ((1 + (Math.min(Math.max(iAverageCommitsPerWeek - 3, 0), 7))) / 7);
     }