Sync knowledge articles with review agent instructions

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

microsoft/knowledge/performance/use-textbuilder-for-loop-string-assembly.bad.al

@@ -0,0 +1,14 @@
+codeunit 50932 "Perf Sample TextConcat Bad"
+{
+    procedure BuildItemList(var Item: Record Item): Text
+    var
+        Result: Text;
+    begin
+        if Item.FindSet() then
+            repeat
+                Result += StrSubstNo('%1,%2', Item."No.", Item.Description);
+            until Item.Next() = 0;
+
+        exit(Result);
+    end;
+}