More human-readable flowcharts/graphs

[pappy74]

(I'm new to Mermaid, and definitely not a Markdown expert, so please let me know if this is ridiculous for whatever reason! Perhaps it becomes impossible to parse?)

I think graph descriptions can be made more human-readable with two changes

• Make node labels optional
• Imply arrow-origin based on indentation.

Eg

flowchart TD
    A[Start] --> B{Is it?}
    B -- Yes --> C[OK]
    C --> D[Rethink]
    D --> B
    B -- No ----> E[End]

becomes

flowchart TD
  [Start]
    --> ISIT{Is it?} 
      -- Yes --> [OK]
        --> [Rethink] ----> ISIT
      -- No --> [End]

I'm guessing there are examples where this would make things less readable, but it would be a nice option for a certain subset.