Fix YAML Timestamp Debounce not Starting with the First Character Change

[pjkaufman]

Relates to #1199

There was an issue mentioned where the YAML Timestamp logic was not having the debounced logic run when a single character was updated. It seems that the debounce function is not automatically started once created, so it needs to be called after creation in this case.

Changes Made:

• Immediately called the debounce function instead of just instantiating it
  • Should allow for the debounce function to start its timer immediately once the first editor change happens