Restore minimized sticky clients

[kosorin]

If a sticky client is minimized on a tag not assigned to it, one has to switch to the tag to be able to restore the minimized client.
A minimized sticky client should be able to be restored with awful.client.restore().

[Aire-One]

Thank you!

[codecov]

Codecov Report

Merging #3709 (3714ec5) into master (4a140ea) will decrease coverage by 0.02%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master    #3709      +/-   ##
==========================================
- Coverage   90.93%   90.91%   -0.03%     
==========================================
  Files         896      896              
  Lines       56630    56634       +4     
==========================================
- Hits        51495    51486       -9     
- Misses       5135     5148      +13     

Flag	Coverage Δ
gcov	90.91% <50.00%> (-0.03%)	⬇️
luacov	93.66% <50.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
lib/awful/client.lua	77.77% <50.00%> (-0.23%)	⬇️
spawn.c	82.58% <0.00%> (-3.51%)	⬇️
tests/test-input-binding.lua	97.50% <0.00%> (-2.00%)	⬇️
tests/examples/screen/template.lua	96.64% <0.00%> (-0.21%)	⬇️
lib/wibox/widget/imagebox.lua	96.42% <0.00%> (+0.89%)	⬆️