path and full_path arguments for output renderers, closes #1179

Output renderer render() and can_render() callbacks can now accept
path and full_path arguments - the path to the HTML version of the
page without the .extension, with and without the query string.

Also fixed path_with_format() so it replaces the extension the current
request used instead of falling back to ?_format=, which Datasette no
longer reads. This broke links generated by renderers such as
datasette-export-notebook, and the URLs returned by ?_extra=renderers
on .json pages.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TzcVp1Cq5yCRW81GiN88JX

tests/plugins/register_output_renderer.py

@@ -5,7 +5,17 @@ from datasette.utils.asgi import Response
 
 
 async def can_render(
-    datasette, columns, rows, sql, query_name, database, table, request, view_name
+    datasette,
+    columns,
+    rows,
+    sql,
+    query_name,
+    database,
+    table,
+    request,
+    path,
+    full_path,
+    view_name,
 ):
     # We stash this on datasette so the calling unit test can see it
     datasette._can_render_saw = {
@@ -17,13 +27,26 @@ async def can_render(
         "database": database,
         "table": table,
         "request": request,
+        "path": path,
+        "full_path": full_path,
         "view_name": view_name,
     }
     return not request.args.get("_no_can_render")
 
 
 async def render_test_all_parameters(
-    datasette, columns, rows, sql, query_name, database, table, request, view_name, data
+    datasette,
+    columns,
+    rows,
+    sql,
+    query_name,
+    database,
+    table,
+    request,
+    path,
+    full_path,
+    view_name,
+    data,
 ):
     headers = {}
     for custom_header in request.args.getlist("header"):
@@ -41,6 +64,8 @@ async def render_test_all_parameters(
                 "database": database,
                 "table": table,
                 "request": request,
+                "path": path,
+                "full_path": full_path,
                 "view_name": view_name,
                 "1+1": result.first()[0],
             },