tweak windrose text label for clarity

[akrherz]

No description provided.

[codecov]

Codecov Report

Merging #594 (e10679b) into main (60c06cf) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #594   +/-   ##
=======================================
  Coverage   96.58%   96.58%           
=======================================
  Files          73       73           
  Lines        9131     9131           
=======================================
  Hits         8819     8819           
  Misses        312      312           

Impacted Files	Coverage Δ
src/pyiem/windrose_utils.py	100.00% <100.00%> (ø)

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