fix(ui2): multiline/color replaced message, expanded cmdline, error messages #38044

Problem:  - Unintentionally inserting lines for a replaced multiline
          message that also has multiple highlights.
          - Scheduled check to see if the expanded cmdline window was
          entered makes it difficult to keep track of what happens when
          the key pressed to dismiss it results in a message.
          - Reading the first line of an error message should be enough
          notice for something going wrong.
          - "search_cmd" messages should not be shown with 0 'cmdheight'.
          - Unable to configure dynamically changed pager height.
          - Enabling UI2 doesn't make sense with no UIs attached.

Solution: - Only insert a line for the first chunk after a newline.
          - Use getmousepos() to check if the expanded cmdline was
          clicked to enter the pager.
          entering the pager to serve as a configuration interface.
          - Don't expand the cmdline for error messages; user can press g<.
          - Don't show "search_cmd" messages with 'cmdheight' set to 0.
          - Change 'eventignorewin' to ensure WinEnter is fired when
          - Have enable() return early when no UIs are attached.

0 files changed, 0 insertions, 0 deletions