chore: replace pub with pub(crate) when possible

src/high_ram.rs

@@ -2,7 +2,7 @@ const HIGH_RAM_SIZE: usize = 0x7F;
 const HIGH_RAM_START_ADDRESS: usize = 0xFF80;
 
 #[derive(Debug, Clone)]
-pub struct HighRam {
+pub(crate) struct HighRam {
     buf: Box<[u8; HIGH_RAM_SIZE]>,
 }
 
@@ -15,11 +15,11 @@ impl Default for HighRam {
 }
 
 impl HighRam {
-    pub fn write_byte(&mut self, addr: u16, byte: u8) {
+    pub(crate) fn write_byte(&mut self, addr: u16, byte: u8) {
         self.buf[addr as usize - HIGH_RAM_START_ADDRESS] = byte;
     }
 
-    pub fn read_byte(&self, addr: u16) -> u8 {
+    pub(crate) fn read_byte(&self, addr: u16) -> u8 {
         self.buf[addr as usize - HIGH_RAM_START_ADDRESS]
     }
 }