Add self to contributors

Author: BNAndras

concepts/string-formatting/.meta/config.json

@@ -1,5 +1,11 @@
 {
   "blurb": "There are four main string formatting methods. A '%' formatting mini-language is supported, but is considered outdated. String interpolation (f-strings) and 'str.format()'are newer, and can be used for complex or conditional substitution. 'string.template()' substitution is used for internationalization, where f-strings will not translate.",
-  "authors": ["valentin-p"],
-  "contributors": ["j08k", "BethanyG"]
+  "authors": [
+    "valentin-p"
+  ],
+  "contributors": [
+    "j08k",
+    "BethanyG",
+    "BNAndras"
+  ]
 }