docs(changelog): make changelog clearer

Removed internal implementation details from changelog and rephrased and reordered
some entries.

docs/CHANGELOG.md

@@ -4,26 +4,11 @@
 
 ### Added
 
-- Add class for existing directories
-- Add function to format a list human-readable
-- Add function to assert that an object is an instance of a specific type
-- Add Python project documentation generator class
-- Add Python namespaces classes
-- Add type checking for the `name` attribute at the constructor of `core.python.namespaces.PythonNamespace`
-- Add check whether sub-namespaces are not empty in `core.python.namespaces.PythonPackageNamespace.namespace`
-- Add feature to get the names of all sub-namespaces of a `core.python.namespaces.PythonPackageNamespace`
-- Add feature to compare `core.python.namespaces.PythonPackageNamespace` instances or `core.python.namespaces.PythonModuleNamespace` instances
-- Add string representation for Python namespace objects
-- Add `PythonDocumentationGenerator` method to collect all namespaces
-- Add class for existing files
-- Add classes for Python function arguments
-- Add classes for Python definitions
-- Add class for Python modules
-- Add feature to get the signature representation of a Python function argument
-- Add class for Python docstrings
-- Add feature to parse Python docstrings
-- Add function to ensure a non-empty string.
-- Add Python definition documentation generator
-- Add function to get the path segments of a path relative to another
-- Add Python module documentation generator
-- Add Python project documentation generator
+- utility class for existing directories
+- utility class for existing files
+- Python project documentation generator
+- Python definition documentation generator
+- Python module documentation generator
+- Python namespaces
+- signature representation of a Python function argument
+- Python docstrings