README: fix markup error (#1480)

Author: methane

README.md

@@ -114,7 +114,7 @@ This has the same effect as an empty DSN string:
 
 ```
 
-`dbname` is escaped by [PathEscape()]()https://pkg.go.dev/net/url#PathEscape) since v1.8.0. If your database name is `dbname/withslash`, it becomes:
+`dbname` is escaped by [PathEscape()](https://pkg.go.dev/net/url#PathEscape) since v1.8.0. If your database name is `dbname/withslash`, it becomes:
 
 ```
 /dbname%2Fwithslash