Add shortcut to open note in a new split pane (PR #202) (#358)

This adds the shortcut `cmd/ctrl + alt + enter` to the search modal to open a found file in a new leaf. I used the term "split" in user-facing text, because I think that's the more common

Some things to note:
- This function ignores the existing "open in new pane by default" setting.
- It also does not check to see if the file is already open. It will continue opening the value in a new split as often as the user wants.

src/components/modals.ts

@@ -68,6 +68,7 @@ abstract class OmnisearchModal extends Modal {
     let openInNewPaneKey: Modifier[]
     let createInCurrentPaneKey: Modifier[]
     let createInNewPaneKey: Modifier[]
+    let openInNewLeafKey: Modifier[] = ['Mod', 'Alt']
     if (settings.openInNewPane) {
       openInCurrentPaneKey = ['Mod']
       openInNewPaneKey = []
@@ -86,6 +87,12 @@ abstract class OmnisearchModal extends Modal {
       eventBus.emit(Action.OpenInNewPane)
     })
 
+    // Open in a new leaf
+    this.scope.register(openInNewLeafKey, 'Enter', e => {
+      e.preventDefault()
+      eventBus.emit(Action.OpenInNewLeaf)
+    })
+
     // Insert link
     this.scope.register(['Alt'], 'Enter', e => {
       e.preventDefault()