Fix docstring

[devmotion]

Addresses #26 (comment).

[torfjelde]

Thanks!

[coveralls]

Pull Request Test Coverage Report for Build 1151075782

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 77.778%

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Totals
Change from base Build 1150932095:	0.0%
Covered Lines:	84
Relevant Lines:	108

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💛 - Coveralls

[codecov]

Codecov Report

Merging #29 (5c101bc) into main (c8fc126) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main      #29   +/-   ##
=======================================
  Coverage   77.77%   77.77%           
=======================================
  Files           1        1           
  Lines         108      108           
=======================================
  Hits           84       84           
  Misses         24       24           

Impacted Files	Coverage Δ
src/varname.jl	77.77% <ø> (ø)

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