[Qt] move SubstituteFonts() above ToolTipToRichTextFilter

- doesn't belong to the ToolTipToRichTextFilter class so move it up
bitcoin-tx: fix build warnings

Cleans up a bunch of:
warning: missing braces around initializer for ‘const<anonymous struct>’
Merge pull request #4696

616c243 bitcoin-tx: fix build warnings (Cory Fields)
Merge pull request #4659

c4bae53 [Qt] move SubstituteFonts() above ToolTipToRichTextFilter (Philip Kaufmann)
[Wallet] Improve ReorderTransactions(..)