Add flag --iexclude-file to backup

doc/040_backup.rst

@@ -142,6 +142,7 @@ the exclude options are:
 -  ``--iexclude`` Same as ``--exclude`` but ignores the case of paths
 -  ``--exclude-caches`` Specified once to exclude folders containing a special file
 -  ``--exclude-file`` Specified one or more times to exclude items listed in a given file
+-  ``--iexclude-file`` Same as ``exclude-file`` but ignores cases like in ``--iexclude``
 -  ``--exclude-if-present foo`` Specified one or more times to exclude a folder's content if it contains a file called ``foo`` (optionally having a given header, no wildcards for the file name supported)
 
 Please see ``restic help backup`` for more specific information about each exclude option.

doc/manual_rest.rst

@@ -97,6 +97,7 @@ command:
       -h, --help                                   help for backup
       -H, --host hostname                          set the hostname for the snapshot manually. To prevent an expensive rescan use the "parent" flag
           --iexclude pattern                       same as --exclude pattern but ignores the casing of filenames
+          --iexclude-file file                     same as --exclude-file but ignores casing of filenames in patterns
           --ignore-inode                           ignore inode number changes when checking for modified files
       -x, --one-file-system                        exclude other file systems
           --parent snapshot                        use this parent snapshot (default: last snapshot in the repo that has the same target files/directories)