Fixed a couple of comments on TimeSpan.SecondsPerTick and Thread.SleepInternal (#18276)

* Fixed comment for TimeSpan.SecondsPerTick

* Fixed comment on Thread.SleepInternal

Signed-off-by: dotnet-bot-corefx-mirror <dotnet-bot@microsoft.com>

Author: alfredmyers

src/Common/src/CoreLib/System/TimeSpan.cs

@@ -34,7 +34,7 @@ public struct TimeSpan : IComparable, IComparable<TimeSpan>, IEquatable<TimeSpan
         private const double MillisecondsPerTick = 1.0 / TicksPerMillisecond;
 
         public const long TicksPerSecond = TicksPerMillisecond * 1000;   // 10,000,000
-        private const double SecondsPerTick = 1.0 / TicksPerSecond;         // 0.0001
+        private const double SecondsPerTick = 1.0 / TicksPerSecond;         // 0.0000001
 
         public const long TicksPerMinute = TicksPerSecond * 60;         // 600,000,000
         private const double MinutesPerTick = 1.0 / TicksPerMinute; // 1.6666666666667e-9