Include module name in the error message

[dnbsd]

Risor's compiler produces very terse error messages, which makes finding the issue in scripts spanning multiple modules difficult.

For instance, the following is an error message from a script which imports another module that is referencing an undefined variable:

$ go run ../cmd/risor main.risor 
compile error: undefined variable "jfaijfeao" (line 1)
exit status 1

The error message omits the name of the module where the error has originated. It also omits the column number. Please, compare with an error produced by the parser:

$ go run ../cmd/risor main.risor
parse error: unterminated block statement

location: line 3, column 4
for{
   ^
exit status 1

Again, module name is not reported, though the provided information is very detailed and helps narrow down the issue to a character.

[robbyt]

@dnbsd it might be helpful to look at the code for how the parser shows the "Friendly" error message:

risor/cmd/risor-api/main.go

Lines 45 to 52 in 7eff207

	result, err := risor.Eval(ctx, string(code))
	if err != nil {
	if friendlyErr, ok := err.(errz.FriendlyError); ok {
	http.Error(w, friendlyErr.FriendlyErrorMessage(), http.StatusBadRequest)
	} else {
	http.Error(w, err.Error(), http.StatusBadRequest)
	}
	return