r.series manual: completed missing method descriptions

raster/r.series/r.series.html

@@ -11,9 +11,11 @@ Following methods are available:
  <li>median: median value
  <li>mode: most frequently occurring value
  <li>minimum: lowest value
+ <li>min_raster: raster map number with the minimum time-series value
  <li>maximum: highest value
- <li>range: range of values (max - min)
+ <li>max_raster: raster map number with the maximum time-series value
  <li>stddev: standard deviation
+ <li>range: range of values (max - min)
  <li>sum: sum of values
  <li>variance: statistical variance
  <li>diversity: number of different values
@@ -21,8 +23,12 @@ Following methods are available:
  <li>offset: linear regression offset
  <li>detcoeff: linear regression coefficient of determination
  <li>tvalue: linear regression t-value
- <li>min_raster: raster map number with the minimum time-series value
- <li>max_raster: raster map number with the maximum time-series value
+ <li>quart1: first quartile
+ <li>quart3: third quartile
+ <li>perc90: ninetieth percentile
+ <li>quantile: arbitrary quantile
+ <li>skewness: skewness
+ <li>kurtosis: kurtosis
 </ul> 
 
 Note that most parameters accept multiple answers, allowing multiple