Kernel: Make backspace \b and delete 0x7F

This is what `vim` seems to expect and imo makes way more sense.

kernel/kernel/Terminal/Serial.cpp

@@ -210,6 +210,8 @@ namespace Kernel
 	void SerialTTY::handle_irq()
 	{
 		uint8_t ch = IO::inb(m_serial.port());
+		if (ch == 0x7F)
+			ch = '\b';
 
 		SpinLockGuard _(m_input_lock);
 		if (m_input.full())

kernel/kernel/Terminal/TTY.cpp

@@ -285,14 +285,6 @@ namespace Kernel
 
 	void TTY::do_backspace()
 	{
-		auto print_backspace =
-			[this]
-			{
-				putchar('\b');
-				putchar(' ');
-				putchar('\b');
-			};
-
 		if (m_output.bytes > 0)
 		{
 			uint8_t last = m_output.buffer[m_output.bytes - 1];
@@ -308,20 +300,20 @@ namespace Kernel
 				}
 				ASSERT(m_output.bytes > 0);
 				m_output.bytes--;
-				print_backspace();
+				putchar('\b');
 			}
 			// Caret notation
 			else if (last < 32 || last == 127)
 			{
 				m_output.bytes--;
-				print_backspace();
-				print_backspace();
+				putchar('\b');
+				putchar('\b');
 			}
 			// Ascii
 			else
 			{
 				m_output.bytes--;
-				print_backspace();
+				putchar('\b');
 			}
 		}
 	}

kernel/kernel/Terminal/VirtualTTY.cpp

@@ -461,7 +461,7 @@ namespace Kernel
 				break;
 			case BS:
 				if (m_column > 0)
-					m_column--;
+					putchar_at(' ', --m_column, m_row);
 				break;
 			case HT:
 				m_column++;
@@ -480,7 +480,7 @@ namespace Kernel
 				break;
 			case ESC:
 				m_state = State::WaitingAnsiEscape;
-				break;;
+				break;
 			default:
 				putchar_at(codepoint, m_column, m_row);
 				m_last_graphic_char = codepoint;