Display both BTC and USD in address history graph

frontend/src/app/shared/pipes/fiat-shortener.pipe.ts

@@ -31,7 +31,7 @@ export class FiatShortenerPipe implements PipeTransform {
       { value: 1, symbol: '' },
       { value: 1e3, symbol: 'k' },
       { value: 1e6, symbol: 'M' },
-      { value: 1e9, symbol: 'G' },
+      { value: 1e9, symbol: 'B' },
       { value: 1e12, symbol: 'T' },
       { value: 1e15, symbol: 'P' },
       { value: 1e18, symbol: 'E' }