v8.19.0

ModelingToolkit v8.19.0

Diff since v8.18.9

Closed issues:

• Collecting symbolic array breaks usage of all on symbolic arrays (#1742)
• Observed equation instead of var returned with getvar (#1743)
• alias_elimination StackOverflowError (#1751)

Merged pull requests:

• return the lhs instead of observable equation from getvar (#1745) (@wsphillips)
• Update authors (#1750) (@YingboMa)
• doc: edits to Events (#1753) (@visr)
• fix a typo in unit check error handling (#1756) (@wsphillips)
• Forward sys to SciMLFunctions (#1758) (@YingboMa)
• Remember to mark the predecessors as processed as well to avoid cycles in alias elimination (#1759) (@YingboMa)