fix: Update collection_name parameter to remove default value for better clarity

app/routers/hadiths.py

@@ -68,7 +68,7 @@ async def get_hadith(hadith_id: str):
              description="Paginated listing of hadiths in a specific collection. "
                          "Collection names use partial matching (e.g. 'bukhari' matches 'Sahih Bukhari').")
 async def list_by_collection(
-    collection_name: str = Field(description="Collection name (partial match). Examples: bukhari, muslim, tirmidhi, abudawud"),
+    collection_name: str,
     page: int = Query(1, ge=1, description="Page number"),
     per_page: int = Query(20, ge=1, le=100, description="Results per page"),
 ):