Fix FSWatcher Unix symlink reading (#108)

Set StringBuilder capacity to PATH_MAX (4096) as Syscall.readlink checks the buffer size and truncates the path to fit in the given buffer.

Author: RFC1920

src/Plugins/Watchers/FSWatcher.cs

@@ -86,6 +86,7 @@ private bool IsFileSymlink(string path)
         private void LoadWatcherSymlink(string path)
         {
             StringBuilder str = StringPool.Take();
+            str.Capacity = 4096;
             try
             {
                 int count = Syscall.readlink(path, str);
@@ -124,7 +125,6 @@ private void LoadWatcherSymlink(string path)
             {
                 StringPool.Return(str);
             }
-
         }
 
         /// <summary>