Change Ctrl-C and move old behavior to Ctrl-Q

This lets Janet be a better unix citizen and lets Ctrl-C
raise an interrupt. Trying to make Janet behave superficially
like a shell by overriding Ctrl-C is not helpful.

janet.1

@@ -64,6 +64,10 @@ Move cursor to the beginning of input line.
 .BR Ctrl\-B
 Move cursor one character to the left.
 
+.TP 16
+.BR Ctrl\-D
+If on a newline, indicate end of stream and exit the repl.
+
 .TP 16
 .BR Ctrl\-E
 Move cursor to the end of input line.
@@ -100,6 +104,10 @@ Delete one word before the cursor.
 .BR Ctrl\-G
 Show documentation for the current symbol under the cursor.
 
+.TP 16
+.BR Ctrl\-Q
+Clear the current command, including already typed lines.
+
 .TP 16
 .BR Alt\-B/Alt\-F
 Move cursor backwards and forwards one word.