Option for scroll value moving more than one line to aid Braille readers

Description of the problem or steps to reproduce

This is a request for an optional feature to aid use for blind people using multiline Braille displays

On multiline line refreshable Braille displays, moving up and down by only one line causes excessive refreshing, whereas moving up and down by X (say 9) lines reduces the number of full pages refreshes.

At the moment, when the user gets to the end of the terminal window it moves up by one line. This causes refreshable Braille displays to refresh the entire display every time someone writes a new line or the line overflows, i.e. all the time. It is noisy and takes time and makes writing with Micro on a multiline Braille display impossible.

However if there were the option to define how many lines it moves up by when the user reaches the end then this effect would be reduced. For example if the user could choose to move up by seven lines then the multiline Braille display would only have to refresh one line (not the whole page) for every line written, except for once in every seven lines written.

Possible syntax:

micro -scrolllines 7

(scrolllines defaults to 1)

Please note I am referring to use using the Canute 360.

Specifications

Version: 2.0.10
Commit hash: b9763856
OS: Raspian
Terminal: xfce4-terminal

The payload names no implementation files or tests. Start by locating the command-line option handling and terminal scrolling path in this Go repository; verify the current one-line behavior. Done means an optional configurable scroll increment, defaulting to one line, that reduces refreshes for multiline Braille use.