tsan: address several review comments


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@168789 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/tsan/rtl/tsan_flags.h b/lib/tsan/rtl/tsan_flags.h
index 41a8a78..86c2af5 100644
--- a/lib/tsan/rtl/tsan_flags.h
+++ b/lib/tsan/rtl/tsan_flags.h
@@ -69,7 +69,7 @@
   // Path to external symbolizer.
   const char *external_symbolizer_path;
   // Per-thread history size, controls how many previous memory accesses
-  // is remembered per thread.  Possible values are [0..7].
+  // are remembered per thread.  Possible values are [0..7].
   // history_size=0 amounts to 32K memory accesses.  Each next value doubles
   // the amount of memory accesses, up to history_size=7 that amounts to
   // 4M memory accesses.  The default value is 2 (128K memory accesses).