Update docstring_rule.md

Author: yuta-nakahara

doc/devdoc/docstring_rule.md

@@ -518,7 +518,7 @@ class LearnModel(base.Posterior,base.PredictiveMixin):
 ```
     xxx : numpy.ndarray, optional
         Vectors of real numbers, 
-        by default zero vectors.
+        by default zero vectors
         If a single vector is input, will be broadcasted.
 ```
 
@@ -527,7 +527,7 @@ class LearnModel(base.Posterior,base.PredictiveMixin):
 ```
     xxx : numpy.ndarray, optional
         Vectors of non-negative numbers, 
-        by default vectors whose elements are all 1.
+        by default vectors whose elements are all 1.0
         If a single vector is input, will be broadcasted.
 ```
 
@@ -536,7 +536,7 @@ class LearnModel(base.Posterior,base.PredictiveMixin):
 ```
     xxx : numpy.ndarray, optional
         Vectors of positive numbers, 
-        by default vectors whose elements are all 1.
+        by default vectors whose elements are all 1.0
         If a single vector is input, will be broadcasted.
 ```
 
@@ -546,7 +546,7 @@ class LearnModel(base.Posterior,base.PredictiveMixin):
     xxx : numpy.ndarray, optional
         Vectors of real numbers in :math:`[0, 1]`, 
         by default vectors such as [1/yyy, 1/yyy, ... , 1/yyy]
-        Sum of the elements of each vector must be 1.
+        Sum of the elements of each vector must be 1.0.
         If a single vector is input, will be broadcasted.
 ```
 
@@ -566,7 +566,7 @@ class LearnModel(base.Posterior,base.PredictiveMixin):
     xxx : numpy.ndarray, optional
         A matrix of real numbers in :math:`[0, 1]`, 
         by default a matrix obtained by stacking [1/yyy, 1/yyy, ... , 1/yyy]
-        Sum of the elements of each row vector must be 1.
+        Sum of the elements of each row vector must be 1.0.
         If a single vector is input, will be broadcasted.
 ```