[clang] [SourceManager] Expose max usage of source location space as a Statistic (PR #96292)

[Utkarsh Saxena via cfe-commits]

================
@@ -46,6 +47,12 @@ using namespace clang;
 using namespace SrcMgr;
 using llvm::MemoryBuffer;
 
+#define DEBUG_TYPE "source-manager"
+
+STATISTIC(
+    MaxUsedSLocBytes,
+    "Maximum number of bytes used by source locations (both loaded and local)");
----------------
usx95 wrote:

nit: It may also be helpful to add some background on why this is important to track.

https://github.com/llvm/llvm-project/pull/96292