Unaligned calendar with locale that has shorter day abbreviations then 3 letters

[wereii]

• output of awesome -v and lua -v

> awesome -v
awesome v4.3-1315-g1932bd017 (Too long)
 • Compiled against Lua 5.3.6 (running with Lua 5.3)
 • API level: 4
 • D-Bus support: yes
 • xcb-errors support: yes
 • execinfo support: yes
 • xcb-randr version: 1.6
 • LGI version: 0.9.2
 • Transparency enabled: yes
 • Custom search paths: no

> lua -v
Lua 5.4.3  Copyright (C) 1994-2021 Lua.org, PUC-Rio

• expected behavior and actual behavior
  Expected that the day names are aligned with day numbers, not like in screenshot:
  

• steps to reproduce the problem:

os.setlocale("cs_CZ.UTF-8")

Possibly has to do something with: #426