Support keeping scroll positions (#837)

* Save mod list scroll position

* Save scroll position for mod description widget

* Description: Don't check for updates on RENDER Thread

Instead of checking if the selected mod changed during RENDER time (on the rendering thread) better do that only when an actual change occurs. This is way more performant.

+ Some additional minor cleanups

- Fix scroll position being reset when returning to the Mods screen
- Optimize description rendering

Author: litetex

src/main/java/com/terraformersmc/modmenu/gui/ModsScreen.java

@@ -236,6 +236,7 @@ protected void init() {
 			this.height - RIGHT_PANE_Y - 96,
 			RIGHT_PANE_Y + 60,
 			textRenderer.fontHeight + 1,
+			this.descriptionListWidget,
 			this
 		);
 		this.descriptionListWidget.setX(this.rightPaneX);
@@ -247,7 +248,7 @@ protected void init() {
 		ClickableWidget doneButton = ButtonWidget.builder(ScreenTexts.DONE, button -> client.setScreen(previousScreen)).position(this.width / 2 + 4, this.height - 28).size(150, 20).build();
 
 		// Initialize data
-		modList.reloadFilters();
+		modList.finalizeInit();
 		this.setFilterOptionsShown(this.keepFilterOptionsShown && this.filterOptionsShown);
 
 		// Add children
@@ -521,35 +522,38 @@ public ModListEntry getSelectedEntry() {
 	}
 
 	public void updateSelectedEntry(ModListEntry entry) {
-		if (entry != null) {
-			this.selected = entry;
-			String modId = selected.getMod().getId();
-			if (this.configureButton != null) {
-				this.configureButton.active = getModHasConfigScreen(modId);
-				this.configureButton.visible = selected != null && getModHasConfigScreen(modId) || modScreenErrors.containsKey(modId);
-				if (modScreenErrors.containsKey(modId)) {
-					Throwable e = modScreenErrors.get(modId);
-					this.configureButton.setTooltip(Tooltip.of(ModMenuScreenTexts.configureError(modId, e)));
-				} else {
-					this.configureButton.setTooltip(Tooltip.of(ModMenuScreenTexts.CONFIGURE));
-				}
-			}
+		if (entry == null) {
+			return;
+		}
+
+		this.selected = entry;
+		String modId = selected.getMod().getId();
+
+		this.descriptionListWidget.updateSelectedModIfRequired(selected.getMod());
 
-			var isMinecraft = modId.equals("minecraft");
-			if (isMinecraft) {
-				this.websiteButton.setMessage(SEND_FEEDBACK_TEXT);
-				this.issuesButton.setMessage(REPORT_BUGS_TEXT);
+		if (this.configureButton != null) {
+
+			this.configureButton.active = getModHasConfigScreen(modId);
+			this.configureButton.visible =
+				selected != null && getModHasConfigScreen(modId) || modScreenErrors.containsKey(modId);
+
+			if (modScreenErrors.containsKey(modId)) {
+				Throwable e = modScreenErrors.get(modId);
+				this.configureButton.setTooltip(Tooltip.of(ModMenuScreenTexts.configureError(modId, e)));
 			} else {
-				this.websiteButton.setMessage(ModMenuScreenTexts.WEBSITE);
-				this.issuesButton.setMessage(ModMenuScreenTexts.ISSUES);
+				this.configureButton.setTooltip(Tooltip.of(ModMenuScreenTexts.CONFIGURE));
 			}
+		}
 
-			this.websiteButton.visible = true;
-			this.websiteButton.active = isMinecraft || selected.getMod().getWebsite() != null;
+		boolean isMinecraft = modId.equals("minecraft");
+		this.websiteButton.setMessage(isMinecraft ? SEND_FEEDBACK_TEXT : ModMenuScreenTexts.WEBSITE);
+		this.issuesButton.setMessage(isMinecraft ? REPORT_BUGS_TEXT : ModMenuScreenTexts.ISSUES);
 
-			this.issuesButton.visible = true;
-			this.issuesButton.active = isMinecraft || selected.getMod().getIssueTracker() != null;
-		}
+		this.websiteButton.visible = true;
+		this.websiteButton.active = isMinecraft || selected.getMod().getWebsite() != null;
+
+		this.issuesButton.visible = true;
+		this.issuesButton.active = isMinecraft || selected.getMod().getIssueTracker() != null;
 	}
 
 	public double getScrollPercent() {