Mention kgtk query in calc.md.
@@ -6,6 +6,10 @@ If no input filename is provided, the default is to read standard input.
The output of a calculation can be written into an existing column or into
a new column, which will be added after all existing columns.
+!!! note
+ [`kgtk query`](https:../query) can perform the same calculations as
+ `kgtk calc` in a more elegant and more general manner.
+
## Usage
```
