[clang] [CIR][NFC] Fix LoweringPrepare pass multi lines summary (PR #148826)

[Andy Kaylor via cfe-commits]

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@@ -73,8 +73,8 @@ def CIRFlattenCFG : Pass<"cir-flatten-cfg"> {
 }
 
 def LoweringPrepare : Pass<"cir-lowering-prepare"> {
-  let summary = "Lower to more fine-grained CIR operations before lowering to
-    other dialects";
+  let summary = "Lower to more fine-grained CIR operations before lowering to "
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andykaylor wrote:

I'm not sure where this is used, but it may be better to shorten it a bit. Perhaps "Prepare to lower CIR to other dialects"?

https://github.com/llvm/llvm-project/pull/148826