Update remaining quickstart examples

Signed-off-by: Clifford Wolf <clifford@clifford.at>

docs/examples/quickstart/cover.sv

@@ -0,0 +1,17 @@
+module top (
+	input clk,
+	input [7:0] din
+);
+	reg [31:0] state = 0;
+
+	always @(posedge clk) begin
+		state <= ((state << 5) + state) ^ din;
+	end
+
+`ifdef FORMAL
+	always @(posedge clk) begin
+		cover (state == 'd 12345678);
+		cover (state == 'h 12345678);
+	end
+`endif
+endmodule