core: Fix typo in for_each sensitive error message

Co-authored-by: Alisdair McDiarmid <alisdair@users.noreply.github.com>

terraform/eval_for_each.go

@@ -62,7 +62,7 @@ func evaluateForEachExpressionValue(expr hcl.Expression, ctx EvalContext, allowU
 		diags = diags.Append(&hcl.Diagnostic{
 			Severity:    hcl.DiagError,
 			Summary:     "Invalid for_each argument",
-			Detail:      "Sensitive variable, or values derived from sensitive variables, cannot be used as for_each arguments. If used, the sensitive value could be exposed as a resource instance key.",
+			Detail:      "Sensitive variables, or values derived from sensitive variables, cannot be used as for_each arguments. If used, the sensitive value could be exposed as a resource instance key.",
 			Subject:     expr.Range().Ptr(),
 			Expression:  expr,
 			EvalContext: hclCtx,