adding missing param and fixing typo (#2084)

Author: aysim319

ansible/templates/nhsn-params-prod.json.j2

@@ -8,7 +8,8 @@
   "indicator": {
     "wip_signal": true,
     "static_file_dir": "./static",
-    "socrata_token": "{{ nhsn_token }}"
+    "socrata_token": "{{ nhsn_token }}",
+    "export_start_date": "2020-08-08"
   },
   "validation": {
     "common": {

nhsn/delphi_nhsn/pull.py

@@ -28,7 +28,7 @@ def pull_data(socrata_token: str, dataset_id: str):
 
 
 def pull_nhsn_data(socrata_token: str, backup_dir: str, custom_run: bool, logger: Optional[logging.Logger] = None):
-    """Pull the latest NSSP ER visits data, and conforms it into a dataset.
+    """Pull the latest NHSN hospital admission data, and conforms it into a dataset.
 
     The output dataset has:
 
@@ -77,7 +77,7 @@ def pull_nhsn_data(socrata_token: str, backup_dir: str, custom_run: bool, logger
 def pull_preliminary_nhsn_data(
     socrata_token: str, backup_dir: str, custom_run: bool, logger: Optional[logging.Logger] = None
 ):
-    """Pull the latest NSSP ER visits data, and conforms it into a dataset.
+    """Pull the latest preliminary NHSN hospital admission data, and conforms it into a dataset.
 
     The output dataset has: