message: Add descriptions for `backgroundImageAlignment`, `backgroundImageOpacity`
  These were already in the `SettingsSchema.md`, so I just updated the `profiles.schema.json` to have the descriptions as well.
  * [x] closes
  * [x] I work here.
  * [x] This is docs.
diff: "topLeft",
  "topRight"
  ],
  + "description": "Sets how the background image aligns to the boundaries of the window. Possible values: \"center\", \"left\", \"top\", \"right\", \"bottom\", \"topLeft\", \"topRight\", \"bottomLeft\", \"bottomRight\"",
  "type": "string"
  },
  "backgroundImageOpacity": {
  - "description": "(Not in SettingsSchema.md)",
  + "description": "Sets the transparency of the background image. Accepts floating point values from 0-1.",
  "maximum": 1,
  "minimum": 0,
  "type": "number"
  