Fix mode buttons visibility for Foundry v10 (#35)

[jagoe]

PR

This PR is supposed to fix #35 by using the new element matchers, falling back to the old matchers for older versions of Foundry.

Changes

• Fix mode buttons parent selection for Foundry v10
  • Defaults to the new matchers (.combat-sidebar .combat-tracker-header)
  • Falls back to the old matchers (#combat > #combat-round)

Notes

• Tested with Foundry v10.288 and Foundry v9.280