feat(diagnostics): Display category value on hover of stacked graph (#139)

Added a tip to stacked line and bar charts to display values of the
category being hovered over.

Examples:

![image](https://github.com/user-attachments/assets/354d4073-ad39-46fe-b042-0abc047a36c8)

![image](https://github.com/user-attachments/assets/3fccfed3-2b93-4910-bc26-f302e8538011)

![image](https://github.com/user-attachments/assets/dcf94c42-56f4-4bd3-a598-93054d020826)

Author: ThomasOrs

webview-ui/src/diagnostics_panel/App.css

@@ -27,6 +27,10 @@ main {
   max-width: initial;
 }
 
+.minecraft-statistic-stacked-line-chart-figure tspan {
+  fill: black;
+}
+
 .minecraft-statistic-stacked-line-chart-swatches {
   font-family: system-ui, sans-serif;
   font-size: 10px;
@@ -91,6 +95,10 @@ main {
   margin-right: 1em;
 }
 
+.minecraft-statistic-stacked-bar-chart tspan {
+  fill: black;
+}
+
 /* .minecraft-statistic-stacked-bar-chart {
   --plot-background: white;
   display: block;

webview-ui/src/diagnostics_panel/controls/MinecraftStatisticStackedBarChart.tsx

@@ -78,7 +78,10 @@ export default function MinecraftStatisticStackedBarChart({
                     x: 'time',
                     y: 'value',
                     fill: 'category',
-                    title: 'category',
+                    title: d => `category: ${d.category}\nvalue: ${d.value}`,
+                    tip: {
+                        fontSize: 12,
+                    },
                 }),
                 Plot.ruleY([0]),
             ],

webview-ui/src/diagnostics_panel/controls/MinecraftStatisticStackedLineChart.tsx

@@ -102,7 +102,10 @@ export default function MinecraftStatisticStackedLineChart({
                     x: 'time',
                     y: 'value',
                     fill: 'category',
-                    title: 'category',
+                    title: d => `category: ${d.category}\nvalue: ${parseFloat(d.value.toFixed(3))}`,
+                    tip: {
+                        fontSize: 12,
+                    },
                 }),
                 Plot.ruleY([0]),
                 targetValue ? Plot.ruleY([targetValue]) : undefined,