Bind i3 bar to primary output

dotfiles/config/i3/config

         separator_symbol "•"
         # other suggestions:
         #     ‧•┇╻╹╹╿═╎╏◆◾║︙⎪∣∕⟘⟙∙∼⦀⦑⦒⦚⧸⧹▓▒░⧻⧺┆˘͡͡ːˌ˷｜･፧።
+        tray_output primary
         colors {
                 statusline         $col_b_stln
                 background         $col_b_bgnd