add warning when @platform='runestone' is inconsistent with publicati…

…on platform/@host (#834)

* add warning when @platform='runestone' is inconsistent with publication platform/@host

* format

pretext/project/__init__.py

@@ -626,6 +626,13 @@ def build(
                     assert self.output_filename is None
                     # This is equivalent to setting `<platform host="runestone">` in the publication file.
                     stringparams_copy.update({"host-platform": "runestone"})
+                    if (
+                        core.get_platform_host(self.publication_abspath().as_posix())
+                        != "runestone"
+                    ):
+                        log.warning(
+                            "The platform host in the publication file is not set to runestone. Since the requested target has @platform='runestone', we will override the publication file's platform host."
+                        )
                 core.html(
                     xml=self.source_abspath(),
                     pub_file=self.publication_abspath().as_posix(),