[PlistSupport] Produce a newline to end plist output files

Summary:
As suggested in the review of D62949, this patch updates the plist
output to have a newline at the end of the file. This makes it so that
the plist output file qualifies as a POSIX text file, which increases
the consumability of the generated plist file in relation to various
tools.

Reviewers: NoQ, sfertile, xingxue, jasonliu, daltenty

Reviewed By: NoQ, xingxue

Subscribers: jsji, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D63041

llvm-svn: 362992

clang/lib/ARCMigrate/PlistReporter.cpp

@@ -120,5 +120,5 @@ void arcmt::writeARCDiagsToPlist(const std::string &outPath,
   o << " </array>\n";
 
   // Finish.
-  o << "</dict>\n</plist>";
+  o << "</dict>\n</plist>\n";
 }

clang/lib/StaticAnalyzer/Core/PlistDiagnostics.cpp

@@ -748,7 +748,7 @@ void PlistDiagnostics::FlushDiagnosticsImpl(
   }
 
   // Finish.
-  o << "</dict>\n</plist>";
+  o << "</dict>\n</plist>\n";
 }
 
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