Change a paragraph to itemizedlist to make translation easier.

Change a hardcoded numbered list to docbook numbered list.
Replace starting balance with opening balance.
Fix typos and minor mistakes.
Fix RewordMiles account name.
Change CoA to Chart of Accounts
Unify currency expression like 12,345 USD for foreign currencies.
Normailze account names.
Change one of the note because English sentenses are too difficult.
Change the date format like Jan. 2, 2020.
Replace Price Editor with Price Database.
Change +ve and -ve to positive and negative, respectively.
Fix according to the pull request comment.