Minimal BASH-like line editing is supported. For the first word, TAB lists possible command completions. Anywhere else TAB lists possible device

Solution 1:

If you know how to get into your BIOS on startup which depends on your model it's one of the F keys on top. Likely F2 or F8, go to the section titled boot or boot devices and move Windows Bootloader higher than Ubuntu. This should make it where your computer will boot Windows by default and you can use the partitioning tools inside of Windows from there to grow your partition back. Search what key to enter your BIOS for your laptop brand. You can also disable Ubuntu from booting on that menu to prevent GRUB from being able to load at all.

Note that this method will not remove GRUB from your system, it will simply allow Windows to boot again.