Show more than bytes for negative file sizes

[hugovk]

Fixes #79.

Changes proposed in this pull request:

• For negative file sizes (for example, to display a change in file size), don't return everything in bytes, use the other prefixes

Before

>>> import humanize
>>> humanize.naturalsize(123456)
'123.5 kB'
>>> humanize.naturalsize(-123456)
'-123456 Bytes'
>>>

After

>>> import humanize
>>> humanize.naturalsize(123456)
'123.5 kB'
>>> humanize.naturalsize(-123456)
'-123.5 kB'
>>>

[tmc]

Codecov Report

Merging #122 into master will not change coverage by %.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #122   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            9         9           
  Lines          410       414    +4     
=========================================
+ Hits           410       414    +4     

Flag	Coverage Δ
#GHA_Ubuntu	100.00% <100.00%> (ø)
#GHA_Windows	?
#GHA_macOS	100.00% <100.00%> (ø)

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[codecov-io]

Codecov Report

Merging #122 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master   #122   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           9      9           
  Lines         410    414    +4     
=====================================
+ Hits          410    414    +4

Flag	Coverage Δ
#GHA_Ubuntu	100% <100%> (ø)	⬆️
#GHA_Windows	100% <100%> (ø)	⬆️
#GHA_macOS	100% <100%> (ø)	⬆️

Impacted Files	Coverage Δ
tests/test_filesize.py	100% <100%> (ø)	⬆️
src/humanize/filesize.py	100% <100%> (ø)	⬆️

---

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Δ = absolute <relative> (impact), ø = not affected, ? = missing data
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[tmc]

Codecov Report

Merging #122 into master will not change coverage by %.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #122   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            9         9           
  Lines          410       414    +4     
=========================================
+ Hits           410       414    +4     

Flag	Coverage Δ
#GHA_Ubuntu	100.00% <100.00%> (ø)
#GHA_Windows	100.00% <100.00%> (ø)
#GHA_macOS	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update aaca29f...8c56ba7. Read the comment docs.