Update PCbuild/readme.txt (merge from 3.5)

diff --cc PCbuild/readme.txt
index 51164e23d0de8925493a8f6f0dc54e9007077678,7e7ab6424bd9a8f3d2c7259d0c51f4187d3eac26..eec7ace78d750b24d457e8768d5bc1b8d647556f
--- 1/PCbuild/readme.txt
--- 2/PCbuild/readme.txt
+++ b/PCbuild/readme.txt
@@@ -49,7 -48,7 +48,7 @@@ Debu
      Used to build Python with extra debugging capabilities, equivalent\r
      to using ./configure --with-pydebug on UNIX.  All binaries built\r
      using this configuration have "_d" added to their name:\r
--    python35_d.dll, python_d.exe, parser_d.pyd, and so on.  Both the\r
++    python36_d.dll, python_d.exe, parser_d.pyd, and so on.  Both the\r
      build and rt (run test) batch files in this directory accept a -d\r
      option for debug builds.  If you are building Python to help with\r
      development of CPython, you will most likely use this configuration.\r