hugetop: print human readable sizes by default

[Franklin-Qi]

Consistent with the hugetop command of procps-ng, change the default size to a format suitable for human reading.

Closed: #687

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 19.20%. Comparing base (c1801fd) to head (d30c3b8).
⚠️ Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
src/uu/hugetop/src/hugetop.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #688   +/-   ##
=======================================
  Coverage   19.20%   19.20%           
=======================================
  Files          68       68           
  Lines       10155    10153    -2     
  Branches      546      547    +1     
=======================================
  Hits         1950     1950           
+ Misses       8205     8203    -2     

Flag	Coverage Δ
macos_latest	6.74% <0.00%> (+<0.01%)	⬆️
ubuntu_latest	19.56% <0.00%> (+<0.01%)	⬆️
windows_latest	0.02% <0.00%> (+<0.01%)	⬆️

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