1119 Support method return types

Small refactor to split out logic for determining method display text and style. Updated documentation
Used regex to parse method statements in class diagrams to extract discrete elements to set display appropriately. Added tests and updated docs

docs/classDiagram.md

@@ -115,7 +115,7 @@ There are two ways to define the members of a class, and regardless of whichever
   class BankAccount
   BankAccount : +String owner
   BankAccount : +BigDecimal balance
-  BankAccount : +deposit(amount) [bool]
+  BankAccount : +deposit(amount) bool
   BankAccount : +withdrawal(amount)
   ```
   ```  mermaid
@@ -132,7 +132,7 @@ There are two ways to define the members of a class, and regardless of whichever
 class BankAccount{
     +String owner
     +BigDecimal balance
-    +deposit(amount) [bool]
+    +deposit(amount) bool
     +withdrawl(amount)
 }
 ```
@@ -147,6 +147,9 @@ class BankAccount{
 ```
 
 
+#### Return Type
+Optionally you can end the method/function definition with the data type that will be returned
+
 #### Visibility
 To specify the visibility of a class member (i.e. any attribute or method), these notations may be placed before the member's name, but it is optional: