doc: codefence available options (gisaid, open, etc)

README.md

@@ -48,7 +48,7 @@ Please follow [installation instructions](https://docs.nextstrain.org/en/latest/
 
 ## Usage
 
-To run pipeline for all available data for generated by ingest:
+To run pipeline for all available data generated by ingest:
 
 ```bash
 nextstrain build .
@@ -78,17 +78,18 @@ The `data_provenances`, `variant_classifications` and `geo_resolutions` are requ
 
 The current available options for `data_provenances` are
 
-- gisaid
-- open
+- `gisaid`
+- `open`
 
 The current available options for `variant_classifications` are
 
-- nextstrain_clades
-- pango_lineages
+- `nextstrain_clades`
+- `pango_lineages`
 
 The current available options for `geo_resolutions` are
-- global
-- usa
+
+- `global`
+- `usa`
 
 ### Data Prep Configurations