CR21-000-T is probably a mistype and should be a jumper CJ21-000-T.
In the excerpt from the datasheet you have given, you can also see that there should be a tolerance listed in the part number if it was a resistor. Because that is also missing from the number, I'd say it is just a 0805 jumper.
The exact part is also no longer available (Mouser product page), but I'd say you just can use any 0805 jumper out there as replacement.
Based on the comments on @derstrom8 answer you were also wondering if this is a jumper like they are used on many boards to select features:
Basically: No, resistor jumpers are used like a normal resistor, so they are soldered onto the board and stay there. Commonly used to cross two signals on the same layer if other methods are not viable. For example in a single layer layout.
They can be used to select options, but typically not for an end user as it requires soldering. You can find this on some development boards though, like on the STM Nucleo (the SB refers to Solder Bridge, in the schematic they look a different to a normal jumper).
During manufacturing you can decide if you want to populate all of the resistor jumpers or not. You can use that information to, say select features or to identify a certain product if the board is used in multiple products.