Default note colours & patterns

A number of defaults for a note's primary visual attributes change from v5.10.1.

In v5, defaults were:

• $Color: 'dark warm gray'
• $Color2: 'light warm gray'
• $Pattern: [no pattern] - equates to 'plain'.

From v5.10.1 there are new defaults:

• $Color: 'warm gray dark'
• $Color2: 'dark warm gray dark'
• $Pattern: 'diagonal'

From v5.11.2 there are new defaults:

• $Color: 'warm gray dark'
• $Color2: 'dark warm gray dark'
• $Pattern: 'solid' - equates to 'plain'

From v5.12.0 there are new defaults:

• $Color: 'warm gray dark'
• $Color2: 'dark warm gray dark'
• $Pattern: 'plain'

The defaults apply to new documents created using a given version or later. Existing documents' defaults are unaffected.