[llvm] Document "%T" as deprecated in CommandGuide/lit.rst

Differential Revision: https://reviews.llvm.org/D48842



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@340677 91177308-0d34-0410-b5e6-96231b3b80d8

docs/CommandGuide/lit.rst

@@ -407,7 +407,7 @@ These are defined in TestRunner.py. The base set of substitutions are:
  %p         same as %S
  %{pathsep} path separator
  %t         temporary file name unique to the test
- %T         temporary directory unique to the test
+ %T         parent directory of %t (not unique, deprecated, do not use)
  %%         %
  ========== ==============