readline: change char to ch to avoid reserved word

lib/readline.js

@@ -839,7 +839,7 @@ var functionKeyCodeRe =
     /^(?:\x1b+)(O|N|\[|\[\[)(?:(\d+)(?:;(\d+))?([~^$])|(?:1;)?(\d+)?([a-zA-Z]))/;
 
 function emitKey(stream, s) {
-  var char,
+  var ch,
       key = {
         name: undefined,
         ctrl: false,
@@ -1029,11 +1029,11 @@ function emitKey(stream, s) {
   }
 
   if (s.length === 1) {
-    char = s;
+    ch = s;
   }
 
-  if (key || char) {
-    stream.emit('keypress', char, key);
+  if (key || ch) {
+    stream.emit('keypress', ch, key);
   }
 }