Short description
Currently when pages are specified to be included but are not found, include fails silently. Currently no warning is issued. If a heading had been specified for the include then the heading is not generated. The behaviour of displaying an indication of includes failing should be similar to way broken links work
Please change include to issue a warning if the page is not found.
Format of warnings
When a specific page is meant to be included the warning should note that the the page may be somewhere else or/and provide a link to the page to allow creating it.
If regex is used to specify pages to include, whether to generate a warning or not is not as clear. In this case I suggest a message noting that no pages were found should be displayed rather than noting an error.
The messages displayed about a page / pages not being found should not be displayed in views not designed for editing (print view or slideshow view).