fzf: update to 0.46.0

* Added two new events
  * result - triggered when the filtering for the current query is complete
    and the result list is ready resize - triggered when the terminal size
  * is changed

* fzf now exports the following environment variables to the child processes
    Variable Description
    FZF_LINES Number of lines fzf takes up excluding padding and margin
    FZF_COLUMNS Number of columns fzf takes up excluding padding and margin
    FZF_TOTAL_COUNT Total number of items
    FZF_MATCH_COUNT Number of matched items
    FZF_SELECT_COUNT Number of selected items
    FZF_QUERY Current query string
    FZF_PROMPT Prompt string
    FZF_ACTION The name of the last action performed

  * This allows you to write sophisticated transformations like so

    # Script to dynamically resize the preview window
    transformer='
      # 1 line for info, another for prompt, and 2 more lines for preview window border
      lines=$(( FZF_LINES - FZF_MATCH_COUNT - 4 ))
      if [[ $FZF_MATCH_COUNT -eq 0 ]]; then
        echo "change-preview-window:hidden"
      elif [[ $lines -gt 3 ]]; then
        echo "change-preview-window:$lines"
      elif [[ $FZF_PREVIEW_LINES -ne 3 ]]; then
        echo "change-preview-window:3"
      fi
    '
    seq 10000 | fzf --preview 'seq {} 10000' --preview-window up \
                    --bind "result:transform:$transformer" \
                    --bind "resize:transform:$transformer"

  * And we're phasing out {fzf:prompt} and {fzf:action}

* Changed: mattn/go-runewidth dependency to rivo/uniseg for accurate
  results

  * Set --ambidouble if your terminal displays ambiguous width characters
    (e.g. box-drawing characters for borders) as 2 columns
  * RUNEWIDTH_EASTASIAN=1 is still respected for backward compatibility,
    but it's recommended that you use this new option instead

* Bug fixes

(iquiw)