Fix sum() and max() example in the docs

[saig0]

Which documentation is missing/incorrect?

• Examples of the functions sum() and max()

Link to the documentation:

• https://camunda.github.io/feel-scala/docs/reference/builtin-functions/feel-built-in-functions-list/#min

Apply changes from downstream documentation project: camunda/camunda-docs#1474

Affected versions:

• 1.10+