[feature-request] Add repeat-command

[anjakefala]

Aim is to have something spiritually similar to vim's . (dot) command.

Design from @ajkerrigan: If there was a repeat command, my intuition would be for it to run the previous cmd longname with any previous input. A z-prefix alternative would run the last command longname with empty, queried input.

Example Workflow

User runs z+ sum on current column Units.
User moves cursor to column Items.
User presses repeat-command. z+ sum is calculated on the current column Items.
User presses z-prefix repeat-command. z+ is exec'd and queries for an aggregator from the user. Once given, it executes on the current column Items.

[anjakefala]

Feature added! ^^
https://www.visidata.org/blog/2020/repeat/

Thank you, @saulpw . 😊