[ci] Comment on what unchanged is

This logic seems flimsy.  For now, just labeled it for what it is.  I think though we need to add extra item to properly track caching changes if formatting failed to do anything.

src/main/java/net/revelc/code/formatter/FormatterMojo.java

@@ -775,6 +775,7 @@ protected void doFormatFile(final File file, final ResultCollector rc, final Pro
 
         // Process the result type
         if (Result.SKIPPED.equals(result)) {
+            // Use unchanged count for files that either 'skipFormattingCache' or cache missed but flagged to skip formatting.
             rc.unchangedCount++;
         } else if (Result.SUCCESS.equals(result)) {
             rc.successCount++;
@@ -1111,7 +1112,7 @@ static class ResultCollector {
         /** The skipped count is incremented for cached files that haven't changed since being cached. */
         int skippedCount;
 
-        /** The unchanged count is incremented on cache misses when a file remains unchanged after formatting. */
+        /** Use unchanged count for files that either 'skipFormattingCache' or cache missed but flagged to skip formatting. */
         int unchangedCount;
 
         /** The read only count. */