recursive building of rss.xml
I have this situation after using preprocessor.rss.
2022-08-07 12:01:09 [INFO] (mdbook::book): Book building has started
2022-08-07 12:01:09 [INFO] (mdbook::book): Running the html backend
2022-08-07 12:01:10 [INFO] (mdbook::cmd::serve): Files changed: ["/home/www-data/projects/mdbook/lessons/src/rss.xml"]
2022-08-07 12:01:10 [INFO] (mdbook::cmd::serve): Building book...
2022-08-07 12:01:10 [INFO] (mdbook::book): Book building has started
2022-08-07 12:01:10 [INFO] (mdbook::book): Running the html backend
2022-08-07 12:01:11 [INFO] (mdbook::cmd::serve): Files changed: ["/home/www-data/projects/mdbook/lessons/src/rss.xml"]
2022-08-07 12:01:11 [INFO] (mdbook::cmd::serve): Building book...
2022-08-07 12:01:11 [INFO] (mdbook::book): Book building has started
2022-08-07 12:01:11 [INFO] (mdbook::book): Running the html backend
2022-08-07 12:01:12 [INFO] (mdbook::cmd::serve): Files changed: ["/home/www-data/projects/mdbook/lessons/src/rss.xml"]
2022-08-07 12:01:12 [INFO] (mdbook::cmd::serve): Building book...
2022-08-07 12:01:12 [INFO] (mdbook::book): Book building has started
2022-08-07 12:01:13 [INFO] (mdbook::book): Running the html backend
2022-08-07 12:01:14 [INFO] (mdbook::cmd::serve): Files changed: ["/home/www-data/projects/mdbook/lessons/src/rss.xml"]
2022-08-07 12:01:14 [INFO] (mdbook::cmd::serve): Building book...
2022-08-07 12:01:14 [INFO] (mdbook::book): Book building has started
2022-08-07 12:01:14 [INFO] (mdbook::book): Running the html backend
2022-08-07 12:01:15 [INFO] (mdbook::cmd::serve): Files changed: ["/home/www-data/projects/mdbook/lessons/src/rss.xml"]
2022-08-07 12:01:15 [INFO] (mdbook::cmd::serve): Building book...
2022-08-07 12:01:15 [INFO] (mdbook::book): Book building has started
2022-08-07 12:01:15 [INFO] (mdbook::book): Running the html backend
2022-08-07 12:01:16 [INFO] (mdbook::cmd::serve): Files changed: ["/home/www-data/projects/mdbook/lessons/src/rss.xml"]
2022-08-07 12:01:16 [INFO] (mdbook::cmd::serve): Building book...
2022-08-07 12:01:16 [INFO] (mdbook::book): Book building has started
2022-08-07 12:01:16 [INFO] (mdbook::book): Running the html backend
2022-08-07 12:01:17 [INFO] (mdbook::cmd::serve): Files changed: ["/home/www-data/projects/mdbook/lessons/src/rss.xml"]
2022-08-07 12:01:17 [INFO] (mdbook::cmd::serve): Building book...
2022-08-07 12:01:17 [INFO] (mdbook::book): Book building has started