Fix copy paste errors and read-out-of-bounds check

src/cpu/instruction.rs

@@ -137,7 +137,7 @@ pub enum Insn {
     /// | 00ff | Enter high-resolution mode
     #[opcode = "0x00ff"]
     hires,
-    /// | fx30 | Enter high-resolution mode
+    /// | fx30 | Load hires font address into vX
     #[opcode = "0xfx30"]
     hfont { x: usize },
     /// | fx75 | Save to "flag registers"

src/cpu/tests.rs

@@ -1149,7 +1149,7 @@ mod behavior {
     fn invalid_pc() {
         let (mut cpu, mut bus) = setup_environment();
         // The bus extends from 0x0..0x1000
-        cpu.pc = 0xfff;
+        cpu.pc = 0x1001;
         match cpu.tick(&mut bus) {
             Err(Error::InvalidAddressRange { range }) => {
                 eprintln!("InvalidAddressRange {{ {range:04x?} }}")