Feature request: Template for n-th differential of function

[Han]

If I recall correctly, one may use "x$n" (with n being a an positive integer) for higher order derivatives as opposed to just using "x" (or a comma-separated list of variables).

The "x,x" notation is likely a template-equivalent of doing: diff(f,x,x) which gives the second derivative of f with respect to x. Similarly, diff(f,x,y) would result in the second mixed partial derivative.

Edit: It appears that the "x$n" works on the command only; e.g. diff("3x^2-2x","x$2") -- I was not able to apply this to the template.