Update reverse-string.md

followed change request

Author: MinerMinerMods

snippets/python/string-manipulation/reverse-string.md

@@ -7,7 +7,7 @@ tags: string,reverse
 
 ```py
 def reverse_string(s:str) -> str:
-	return s[::-1]
+    return s[::-1]
 
 # Usage:
 reverse_string('hello') # Returns: 'olleh'