Fixing FileInput hook with Pelican version 4.5.0

It is used in rst_include plugin to prefix all rst file with aliases
defined in include.rst
2 jobs for fix_pelican_4.5.0 in 1 minute and 37 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Deps
passed #30361
pelican
deps

00:00:02

 
  Build
passed #30362
docker
build

00:01:34