[Clang][Frontend] Change help text for --offload-host-device

I believe the help text for the flag `--offload-host-device` is wrong. Currently, the help text says "Only compile for the offloading host." but the flag alias with `--cuda-compile-host-device` which
has the help text "Compile CUDA code for both host and device (default). Has no effect on non-CUDA compilations."

Fixes #64243

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D156641

clang/include/clang/Driver/Options.td

@@ -2875,7 +2875,7 @@ def offload_device_only : Flag<["--"], "offload-device-only">, Flags<[FlangOptio
 def offload_host_only : Flag<["--"], "offload-host-only">, Flags<[FlangOption]>,
   HelpText<"Only compile for the offloading host.">;
 def offload_host_device : Flag<["--"], "offload-host-device">, Flags<[FlangOption]>,
-  HelpText<"Only compile for the offloading host.">;
+  HelpText<"Compile for both the offloading host and device (default).">;
 def cuda_device_only : Flag<["--"], "cuda-device-only">, Alias<offload_device_only>,
   HelpText<"Compile CUDA code for device only">;
 def cuda_host_only : Flag<["--"], "cuda-host-only">, Alias<offload_host_only>,

flang/test/Driver/driver-help-hidden.f90

@@ -84,7 +84,7 @@
 ! CHECK-NEXT: -module-dir <dir>      Put MODULE files in <dir>
 ! CHECK-NEXT: -nocpp                 Disable predefined and command line preprocessor macros
 ! CHECK-NEXT: --offload-device-only   Only compile for the offloading device.
-! CHECK-NEXT: --offload-host-device   Only compile for the offloading host.
+! CHECK-NEXT: --offload-host-device   Compile for both the offloading host and device (default).
 ! CHECK-NEXT: --offload-host-only     Only compile for the offloading host.
 ! CHECK-NEXT: -o <file> Write output to <file>
 ! CHECK-NEXT: -pedantic              Warn on language extensions

flang/test/Driver/driver-help.f90

@@ -80,7 +80,7 @@
 ! HELP-NEXT: -module-dir <dir>      Put MODULE files in <dir>
 ! HELP-NEXT: -nocpp                 Disable predefined and command line preprocessor macros
 ! HELP-NEXT: --offload-device-only   Only compile for the offloading device.
-! HELP-NEXT: --offload-host-device   Only compile for the offloading host.
+! HELP-NEXT: --offload-host-device   Compile for both the offloading host and device (default).
 ! HELP-NEXT: --offload-host-only     Only compile for the offloading host.
 ! HELP-NEXT: -o <file>              Write output to <file>
 ! HELP-NEXT: -pedantic              Warn on language extensions