[Feature]: Textual Notation: Indentation

[antoineatstariongroup]

What type of issue is this?

• Bug report
• Feature request

Prerequisites

• I have written a descriptive issue title
• I have verified that I am running the latest version of the SysML2.NET
• I have searched open and closed issues to ensure it has not already been reported

Description

The current Textual Notation does not uses indentation, which makes content hard to read.

Writers has to use a stringBuilder that is indentation aware to ease readability

Steps to Reproduce

System Configuration

• SysML2.NET version:
• Environment (Operating system, version and so on):
• .NET Framework version:
• Additional information: