fix: add missing exports

Author: ianwremmel

src/data-display/gauge/index.ts

@@ -0,0 +1 @@
+export * from './gauge';

src/data-display/index.ts

@@ -0,0 +1,3 @@
+export * from './fact';
+export * from './gauge';
+export * from './line-chart';

src/index.tsx

@@ -2,6 +2,7 @@ export * from './alert';
 export * from './card';
 export * from './code';
 export * from './core';
+export * from './data-display';
 export * from './description';
 export * from './link';
 export * from './pager';