Remove unnecessary spaces from document object’s page_content of BiliBiliLoader (#4619)

- Remove unnecessary spaces from document object’s page_content of
BiliBiliLoader
- Fix BiliBiliLoader document and test file

docs/modules/indexes/document_loaders/examples/bilibili.ipynb

@@ -5,7 +5,7 @@
    "id": "66a7777e",
    "metadata": {},
    "source": [
-    "# Bilibili\n",
+    "# BiliBili\n",
     "\n",
     ">[Bilibili](https://www.bilibili.tv/) is one of the most beloved long-form video sites in China.\n",
     "\n",
@@ -35,7 +35,7 @@
    },
    "outputs": [],
    "source": [
-    "from langchain.document_loaders.bilibili import BiliBiliLoader"
+    "from langchain.document_loaders import BiliBiliLoader"
    ]
   },
   {