Update xlsx arg descripton (xslx -> xlsx) (#2050)

README.md

@@ -70,7 +70,7 @@ optional arguments:
                         path.
   --csv                 Create Comma-Separated Values (CSV) File.
   --xlsx                Create the standard file for the modern Microsoft Excel
-                        spreadsheet (xslx).
+                        spreadsheet (xlsx).
   --site SITE_NAME      Limit analysis to just the listed sites. Add multiple options to
                         specify more than one site.
   --proxy PROXY_URL, -p PROXY_URL

sherlock/sherlock.py

@@ -555,7 +555,7 @@ def main():
         action="store_true",
         dest="xlsx",
         default=False,
-        help="Create the standard file for the modern Microsoft Excel spreadsheet (xslx).",
+        help="Create the standard file for the modern Microsoft Excel spreadsheet (xlsx).",
     )
     parser.add_argument(
         "--site",