Added pretty trivial summary line.

Author: pnkfelix

triage/2021-09-21.md

@@ -1,8 +1,8 @@
 # 2021-09-21 Triage Log
 
-TODO: Summary
+A nice week: more improvements than regressions.
 
-Triage done by **@???**.
+Triage done by **@pnkfelix**.
 Revision range: [9f85cd6f2ab2769c16e89dcdddb3e11d9736b351..7743c9fadd64886d537966ba224b9c20e6014a59](https://perf.rust-lang.org/?start=9f85cd6f2ab2769c16e89dcdddb3e11d9736b351&end=7743c9fadd64886d537966ba224b9c20e6014a59&absolute=false&stat=instructions%3Au)
 
 2 Regressions, 4 Improvements, 8 Mixed; ??? of them in rollups