Add meta descriptions for mempool and liquid

frontend/src/app/components/block-rewards-graph/block-rewards-graph.component.ts

@@ -63,6 +63,7 @@ export class BlockRewardsGraphComponent implements OnInit {
 
   ngOnInit(): void {
     this.seoService.setTitle($localize`:@@8ba8fe810458280a83df7fdf4c614dfc1a826445:Block Rewards`);
+    this.seoService.setDescription($localize`:@@meta.description.bitcoin.graphs.block-rewards:See Bitcoin block rewards in BTC and USD visualized over time. Block rewards are the total funds miners earn from the block subsidy and fees.`);
     this.miningWindowPreference = this.miningService.getDefaultTimespan('3m');
     this.radioGroupForm = this.formBuilder.group({ dateSpan: this.miningWindowPreference });
     this.radioGroupForm.controls.dateSpan.setValue(this.miningWindowPreference);
@@ -191,7 +192,7 @@ export class BlockRewardsGraphComponent implements OnInit {
           {
             name: 'Rewards ' + this.currency,
             inactiveColor: 'rgb(110, 112, 121)',
-            textStyle: {  
+            textStyle: {
               color: 'white',
             },
             icon: 'roundRect',