v2.10.1: fixes for macros, repeat, and guix build

v2.10.1 (2022-09-12)

This release has a few minor improvements and several bugfixes. Notably, macros and repeat in 2.10 were not working, and the Guix build was broken also. These are fixed.

Some of the other improvements:

• option to disable histogram with disp_histlen or disp_histogram set to 0 or empty string
• add guard-sheet-off command to unguard sheet (thanks @hanfried for PR #1517)
• add zo (open-cell) command to open file or url from path in current cell
• fixed bugs: #1499 #1494 #1513 #1510 #804
• fewer than 50% of commits (13/28) in this release were authored by Saul

Also there are new decorators, @Extensible.before and @Extensible.after, to make it easier to extend existing functions.

For a complete list of changes, see the [CHANGELOG](https://github.com/saulpw/visidata/blob/develop/CHANGELOG.md#v2101-2022-09-12).