Fix formatting and add note about provider fields

optimade.rst

@@ -4521,30 +4521,36 @@ The OPTIMADE JSON Lines format then extends these rules with the following conve
   - First the base info response MUST be provided, following the description at `Base Info Endpoint`_.
   - The next lines MUST contain the entry info endpoint responses for the all entry types present later in the file, as described in `Entry Listing Info Endpoints`_. 
     These MUST appear in alphabetical order by entry type name.
-- The remaining lines of the file contain data entries themselves, described in `Entry Listng JSON Response Schema`_.
+- The remaining lines of the file contain data entries themselves, described in `Entry Listing JSON Response Schema`_.
   Again, these MUST appear in block alphabetical order by entry type name, but can appear in any order within those blocks.
 - Finally, any custom extension endpoints (see `Custom Extension Endpoints`_), if present and desirable, MUST appear at the end of the file.
 
 This leaves the following overall file structure:
 
-.. code :: text
+.. code :: txt
+
   <header>
   <optional metadata>
   <base info response>
   <entry info responses>
   <entries block ordered by entry type>
   <optional custom extension endpoints>
+  
 
-- Information about prefixes and provider fields
+This JSONL format can also be used to share provider-specific properties.
+These should be consistent with any external definitions, and where appropriate, prefixes tied to the tools used to generate the file should be used.
+It is RECOMMENDED that custom properties are defined in full within the JSONL file, or pointed to a specific versioned property definition.
 
 Example OPTIMADE JSON Lines File
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. code :: json
+.. code :: jsonc
+
   {"x-optimade": {"api_version": "1.2.0"}}
   {"meta": {"time_stamp": "2024-07-19T11:47:10Z", "data_returned": 6, "provider": {"name": "Example JSONL", "description": "An example JSONL file.", "prefix": "_exmpl"}}}
-  {"type": "info", "id": "/", "attributes": {"api_version": "1.2.0", "available_api_versions": ["1.2.0"], "formats": ["json"], "entry_types_by_format": {"json": ["references", "structures"]}, "license": "https://example.com/licenses/example_license.html"} "homepage": "https://example.com", "name": "Example API", "provider": {"description": "A simple example provider", "name": "Example Provider"}}}
+  {"type": "info", "id": "/", "attributes": {"api_version": "1.2.0", "available_api_versions": ["1.2.0"], "formats": ["json"], "entry_types_by_format": {"json": ["references", "structures"]}, "license": "https://example.com/licenses/example_license.html"}, "homepage": "https://example.com", "name": "Example API", "provider": {"description": "A simple example provider", "name": "Example Provider"}}}
   {"type": "info", "id": "references", ...}
   {"type": "info", "id": "structures", ...}
-  {"type": "structures", "id": "1", "attributes": {...}
+  {"type": "structures", "id": "1", "attributes": {...}}
+  {"type": "references", "id": "2", "attributes": {...}}