chore: apply review suggestions

* pref: optimize `common` rules and matchers
* chore: rename diagrams services to short form
* chore: sort imports

packages/parser/src/language/pie/valueConverter.ts

@@ -0,0 +1,17 @@
+import type { CstNode, GrammarAST, ValueType } from 'langium';
+
+import { MermaidValueConverter } from '../common/valueConverter.js';
+
+export class PieValueConverter extends MermaidValueConverter {
+  protected runCustomConverter(
+    rule: GrammarAST.AbstractRule,
+    input: string,
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    _cstNode: CstNode
+  ): ValueType | undefined {
+    if (rule.name !== 'PIE_SECTION_LABEL') {
+      return undefined;
+    }
+    return input.replace(/"/g, '').trim();
+  }
+}