and some cleaning

Author: SergeStinckwich

src/Math-Core-Distribution/PMErfApproximation.class.st

@@ -1,9 +1,11 @@
 "
-A PMErfApproximation is a five term approximation to erf(x). This is a singleton class encapsulating the approximation. 
+A `PMErfApproximation` is a five term approximation to erf(x). This is a singleton class encapsulating the approximation. 
 
 Use with 
 
+```
 PMErfApproximation new value: aNumber
+```
 
 to receive erf(x). The result of the error function lies between zero and one.
 

src/Math-Core-Distribution/PMMitchellMooreGenerator.class.st

@@ -9,7 +9,7 @@ Class {
 	#classVars : [
 		'UniqueInstance'
 	],
-	#category : 'Math-Core-Distribution'
+	#category : #'Math-Core-Distribution'
 }
 
 { #category : #creation }
@@ -70,11 +70,10 @@ PMMitchellMooreGenerator >> floatValue [
 
 { #category : #initialization }
 PMMitchellMooreGenerator >> initialize: anArray lowIndex: anInteger [
-	
+
 	randoms := anArray.
 	lowIndex := anInteger.
-	highIndex := randoms size.
-	^self
+	highIndex := randoms size
 ]
 
 { #category : #information }

src/Math-Core-Distribution/PMProbabilityDensity.class.st

@@ -4,7 +4,7 @@ Class {
 	#instVars : [
 		'flatGenerator'
 	],
-	#category : 'Math-Core-Distribution'
+	#category : #'Math-Core-Distribution'
 }
 
 { #category : #information }
@@ -108,10 +108,11 @@ PMProbabilityDensity >> kurtosis [
 
 { #category : #information }
 PMProbabilityDensity >> parameters [
+
 	"Returns an Array containing the parameters of the distribution. 
 	It is used to print out the distribution and for fitting."
 
-	^self subclassResponsibility
+	self subclassResponsibility
 ]
 
 { #category : #display }