Fix typo from terminusdb/terminusdb-docs/pull/213

Original issue:
terminusdb/terminusdb-docs#213

```diff
documents = [{ '@type' : 'Person', 'name' : "Jim" },
            { '@type' : 'Person', 'name' : "Jill" }]
-results = client.insert_document(document)
+results = client.insert_document(documents)
```

Author: alexander-mart

schema/all_documents.json

@@ -1024,7 +1024,7 @@
     "slug": "add-documents-with-python-client",
     "body": {
       "@type": "Body",
-      "value": "After you have imported the `terminusdb_client`, and [created a client](/docs/connect-with-python-client/), [connected to a database](/docs/connect-with-python-client/), and [added a schema](/docs/add-a-schema-with-the-python-client/), you can then use this client to insert a document that conforms to the schema.\n\n## Insert a document\n\nTo insert a document, you should use `insert_document`:\n\n```\ndocument = { '@type' : 'Person', 'name' : \"Jim\" }\nresults = client.insert_document(document)\n```\n\n## Insert multiple documents\n\nTo insert multiple documents you can also invoke `insert_document`:\n\n```\ndocuments = [{ '@type' : 'Person', 'name' : \"Jim\" },\n            { '@type' : 'Person', 'name' : \"Jill\" }]\nresults = client.insert_document(document)\n```\n\n## Insert schema document(s)\n\nAdditionally, you can update the schema itself by adding schema documents:\n\n```\nschema = { '@type' : 'Class', '@id' : 'Person', 'name' : 'xsd:string'}\nresults = client.insert_document(schema,graph_type=\"schema\")\n```"
+      "value": "After you have imported the `terminusdb_client`, and [created a client](/docs/connect-with-python-client/), [connected to a database](/docs/connect-with-python-client/), and [added a schema](/docs/add-a-schema-with-the-python-client/), you can then use this client to insert a document that conforms to the schema.\n\n## Insert a document\n\nTo insert a document, you should use `insert_document`:\n\n```\ndocument = { '@type' : 'Person', 'name' : \"Jim\" }\nresults = client.insert_document(document)\n```\n\n## Insert multiple documents\n\nTo insert multiple documents you can also invoke `insert_document`:\n\n```\ndocuments = [{ '@type' : 'Person', 'name' : \"Jim\" },\n            { '@type' : 'Person', 'name' : \"Jill\" }]\nresults = client.insert_document(documents)\n```\n\n## Insert schema document(s)\n\nAdditionally, you can update the schema itself by adding schema documents:\n\n```\nschema = { '@type' : 'Class', '@id' : 'Person', 'name' : 'xsd:string'}\nresults = client.insert_document(schema,graph_type=\"schema\")\n```"
     },
     "seo_metadata": {
       "@type": "SEOMetadata",