Include the autosuggestion in history if it was truncated

https://github.com/fish-shell/fish-shell/issues/650

reader.cpp

@@ -3517,9 +3517,9 @@ const wchar_t *reader_readline(void)
                     data->search_buff.append(data->command_line);
                     data->history_search = history_search_t(*data->history, data->search_buff, HISTORY_SEARCH_TYPE_CONTAINS);
 
-                    /* Skip the autosuggestion as history */
+                    /* Skip the autosuggestion as history unless it was truncated */
                     const wcstring &suggest = data->autosuggestion;
-                    if (! suggest.empty())
+                    if (! suggest.empty() && ! data->screen.autosuggestion_is_truncated)
                     {
                         data->history_search.skip_matches(wcstring_list_t(&suggest, 1 + &suggest));
                     }

screen.cpp

@@ -1245,6 +1245,9 @@ void s_write(screen_t *s,
     /* Compute a layout */
     const screen_layout_t layout = compute_layout(s, screen_width, left_prompt, right_prompt, explicit_command_line, autosuggestion, indent);
 
+    /* Determine whether, if we have an autosuggestion, it was truncated */
+    s->autosuggestion_is_truncated = ! autosuggestion.empty() && autosuggestion != layout.autosuggestion;
+
     /* Clear the desired screen */
     s->desired.resize(0);
     s->desired.cursor.x = s->desired.cursor.y = 0;
@@ -1402,6 +1405,7 @@ screen_t::screen_t() :
     last_right_prompt_width(),
     actual_width(SCREEN_WIDTH_UNINITIALIZED),
     soft_wrap_location(INVALID_LOCATION),
+    autosuggestion_is_truncated(false),
     need_clear_lines(false),
     need_clear_screen(false),
     actual_lines_before_reset(0),

screen.h

@@ -141,6 +141,9 @@ public:
     /** If we support soft wrapping, we can output to this location without any cursor motion. */
     screen_data_t::cursor_t soft_wrap_location;
     
+    /** Whether the last-drawn autosuggestion (if any) is truncated, or hidden entirely */
+    bool autosuggestion_is_truncated;
+
     /**
      This flag is set to true when there is reason to suspect that
      the parts of the screen lines where the actual content is not