Merge pull request github#19048 from github/redsun82/swift-count-nodes

Swift: add summary about total extracted nodes

Author: redsun82

swift/ql/src/change-notes/2025-03-18-number_of_nodes.md

@@ -0,0 +1,4 @@
+---
+category: newQuery
+---
+* Added a new summary query counting the total number of extracted AST nodes.

swift/ql/src/diagnostics/internal/AstNodes.ql

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+/**
+ * @name Number of extracted AST nodes
+ * @description Count all AST nodes.
+ * @kind metric
+ * @id swift/diagnostics/ast-nodes
+ * @tags summary
+ */
+
+import swift
+
+select count(AstNode n)