Let print_timer() print a Section

[johnomotani]

Allow print_timer() to print Section as well as TimerOutput.

The 1.0 update (I guess) meant that to["foo"] is a Section, not a TimerOutput. This meant that print_timer(to["foo"]) errored. It would be possible to work around this by calling show_table() directly, but print_timer() is part of the public API and show_table() is not, so this looks like a bug. To reproduce (or see that it is fixed with this PR):

using TimerOutputs
to = TimerOutput()
@timeit to "foo" sleep(1)
print_timer(to["foo"])

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 94.93%. Comparing base (ada4b6c) to head (7adc294).
⚠️ Report is 46 commits behind head on master.

Files with missing lines	Patch %	Lines
src/printing.jl	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #239       +/-   ##
===========================================
+ Coverage   84.82%   94.93%   +10.10%     
===========================================
  Files           5        9        +4     
  Lines         323      948      +625     
===========================================
+ Hits          274      900      +626     
+ Misses         49       48        -1     

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[KristofferC]

Could maybe use a test

[johnomotani]

Could maybe use a test

What kind of test is appropriate? Just something that calls print_timer() with a Section and sees that it does not error? I can probably add that next week some time.