Per #2058, correct the documented equation for Bias Ratio.

docs/Users_Guide/appendixC.rst

@@ -1010,7 +1010,7 @@ Called "BIAS_RATIO" in ECNT output :numref:`table_ES_header_info_es_out_ECNT`
 
 The bias ratio (BIAS_RATIO) is computed when verifying an ensemble against gridded analyses or point observations. It is defined as the mean error (ME) of ensemble member values greater than or equal to the observation value divided by the mean absolute error (MAE) of ensemble member values less than the observation value.
 
-.. math:: \text{BIAS_RATIO} = \frac{ \frac{ \sum_{f_i >= o_i} f_i - o_i }{ \text{count}(f_i >= o_i) } }{ \frac{ \sum_{f_i < o_i}|f_i - o_i| }{ \text{count}(f_i < o_i) } }
+.. math:: \text{BIAS_RATIO} = \frac{ \frac{ \sum_{f_i >= o_i} f_i - o_i }{ \text{count}(f_i >= o_i) } }{ \frac{ | \sum_{f_i < o_i} f_i - o_i | }{ \text{count}(f_i < o_i) } }
 
 TODO: Define the perfect score and advice on interpretation.