[llvm] Proofread TableGen/ProgRef.rst

[kazutakahirata]

No description provided.

[llvm-ci]

LLVM Buildbot has detected a new failure on builder ppc64le-mlir-rhel-clang running on ppc64le-mlir-rhel-test while building llvm at step 5 "build-check-mlir-build-only".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/129/builds/30748

Here is the relevant piece of the build log for the reference

Step 5 (build-check-mlir-build-only) failure: build (failure) (timed out)
...
186.868 [1521/18/2899] Building TestOps.8.cpp...
186.869 [1521/17/2900] Building TestOps.9.cpp...
186.883 [1521/16/2901] Creating library symlink lib/libmlir_runner_utils.so
186.978 [1521/15/2902] Linking CXX executable bin/tblgen-lsp-server
187.615 [1521/14/2903] Building TestOps.cpp.inc...
187.716 [1521/13/2904] Building TestOps.h.inc...
202.514 [1521/12/2905] Building CXX object tools/mlir/lib/Interfaces/CMakeFiles/obj.MLIRParallelCombiningOpInterface.dir/ParallelCombiningOpInterface.cpp.o
224.999 [1521/11/2906] Building CXX object tools/mlir/lib/Tools/mlir-lsp-server/CMakeFiles/obj.MLIRLspServerLib.dir/LSPServer.cpp.o
233.296 [1521/10/2907] Building CXX object tools/mlir/lib/Tools/mlir-lsp-server/CMakeFiles/obj.MLIRLspServerLib.dir/MlirLspServerMain.cpp.o
241.630 [1521/9/2908] Building CXX object tools/mlir/lib/Tools/mlir-lsp-server/CMakeFiles/obj.MLIRLspServerLib.dir/Protocol.cpp.o
command timed out: 1200 seconds without output running [b'ninja', b'check-mlir-build-only'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1442.237014