Fix double-space in exception message (GH-29955)

(cherry picked from commit c602c1b)

Co-authored-by: Ned Batchelder <[email protected]>

Author: miss-islington

Lib/statistics.py

@@ -374,7 +374,7 @@ def geometric_mean(data):
         return exp(fmean(map(log, data)))
     except ValueError:
         raise StatisticsError('geometric mean requires a non-empty dataset '
-                              ' containing positive numbers') from None
+                              'containing positive numbers') from None
 
 
 def harmonic_mean(data, weights=None):