Change lookahead_list into a queue

Using builtin `commandline -f`, one would expect to have commands executed in
the order that they were given.  This motivates the change to a queue.

Unfortunately, fish internals still need lookahead_list to act as a stack.  Add
and rename functions to support both cases and have lookahead_list as
a std::deque internally.

This code is delicate, and we should probably dog-food this in nightly for
a while before the next-minor release.

Fixes #1567

1 files changed, 2 insertions, 2 deletions

diff --git a/builtin_commandline.cpp b/builtin_commandline.cpp
index 7f576aff..339cb0d1 100644
--- a/builtin_commandline.cpp
+++ b/builtin_commandline.cpp
@@ -455,10 +455,10 @@ static int builtin_commandline(parser_t &parser, wchar_t **argv)
             {
                 /*
                   input_unreadch inserts the specified keypress or
-                  readline function at the top of the stack of unused
+                  readline function at the back of the queue of unused
                   keypresses
                 */
-                input_unreadch(c);
+                input_queue_ch(c);
             }
             else
             {