Hi 
you need to repair grub, but in rescue mode you have to set the correct path You need to figure out which partition has the boot directory, like this:
ls (hd0,6)/boot
(i guess windows overwrite it, grub thinks that the windows partition is the linux partition and says the filesystem is unknown, because it is ntfs).
Then set the correct path and boot:
set root=(hd0,6)
set prefix=(hd0,6)/boot/grub
insmod normal
normal
After that, you need to reinstall grub: GRUB/Restore the GRUB Bootloader - Manjaro