chore(docs): updated comments in typescript def

Updated based on #1181

types/log4js.d.ts

@@ -168,7 +168,7 @@ export interface DateFileAppender {
   filename: string;
   // defaults to basic layout
   layout?: Layout;
-  // defaults to .yyyy-MM-dd - the pattern to use to determine when to roll the logs.
+  // defaults to yyyy-MM-dd - the pattern to use to determine when to roll the logs.
   /**
    * The following strings are recognised in the pattern:
    *  - yyyy : the full year, use yy for just the last two digits
@@ -187,13 +187,13 @@ export interface DateFileAppender {
   mode?: number;
   // default ‘a’
   flags?: string;
-  // compress the backup files during rolling (backup files will have .gz extension)(default false)
+  // compress the backup files using gzip (backup files will have .gz extension)(default false)
   compress?: boolean;
-  // include the pattern in the name of the current log file as well as the backups.(default false)
+  // include the pattern in the name of the current log file.(default false)
   alwaysIncludePattern?: boolean;
   // keep the file extension when rotating logs
   keepFileExt?: boolean;
-  // if this value is greater than zero, then files older than that many days will be deleted during log rolling.(default 0)
+  // the number of old files that matches the pattern to keep (excluding the hot file).(default )
   numBackups?: number;
 }