Fix some vaild lang_result that get incorrectly fallbacked

Author: libenc

src/yagooglesearch/__init__.py

@@ -144,7 +144,11 @@ def __init__(
         self.query = urllib.parse.quote_plus(query)
         self.tld = tld
         self.lang_html_ui = lang_html_ui
-        self.lang_result = lang_result.lower()
+        self.lang_result = (
+            lang_result.lower()
+            if "-" not in lang_result
+            else f"{lang_result.split('-')[0].lower()}-{lang_result.split('-')[1].upper()}"
+        )
         self.tbs = tbs
         self.safe = safe
         self.start = start