The godot editor has a built-in documentation.
You can Ctrl+Click on a type (Vector2 in this case) and see it's entire description.
It says it doesn't have a
clamped() function, you can confirm it for yourself.
Instead it has a function called
clamp(), but it doesn't take the same kind of parameter.
Checking out the online documentation (specifically the 3.x) version, you can see in the description of
Vector2.clamped() that it is depricated, and
limit_length() should be used instead. This function is present in the 4.0 version as well.