Fix the special string in docs to check for similar usernames: {%} -> {?}

resolve #1968

README.md

@@ -46,11 +46,11 @@ usage: sherlock [-h] [--version] [--verbose] [--folderoutput FOLDEROUTPUT]
                 [--browse] [--local] [--nsfw]
                 USERNAMES [USERNAMES ...]
 
-Sherlock: Find Usernames Across Social Networks (Version 0.14.2)
+Sherlock: Find Usernames Across Social Networks (Version 0.14.3)
 
 positional arguments:
   USERNAMES             One or more usernames to check with social networks.
-                        Check similar usernames using {%} (replace to '_', '-', '.').
+                        Check similar usernames using {?} (replace to '_', '-', '.').
 
 optional arguments:
   -h, --help            show this help message and exit

sherlock/sherlock.py

@@ -617,7 +617,7 @@ def main():
         nargs="+",
         metavar="USERNAMES",
         action="store",
-        help="One or more usernames to check with social networks. Check similar usernames using {%%} (replace to '_', '-', '.').",
+        help="One or more usernames to check with social networks. Check similar usernames using {?} (replace to '_', '-', '.').",
     )
     parser.add_argument(
         "--browse",