Remove "go generate" from the docs

docs/CONTRIBUTING.md

@@ -84,14 +84,13 @@ step.
 
 #### generated code
 
-A significant portion of the project's source code is generated, with the goal being to
+A significant portion of the project's source code is generated, to
 eliminate repetitive maintenance where other type-safe abstraction is impractical or
 impossible with Go versions `< 1.18`. In a future where the eldest Go version supported is
 `1.18.x`, there will likely be efforts to take advantage of
 [generics](https://go.dev/doc/tutorial/generics).
 
-The built-in `go generate` command is used to run the commands specified in
-`//go:generate` directives. Each such command runs a file that also supports a command
+Generator scripts also support command
 line help system which may be consulted for further information, e.g.:
 
 ```sh