[RISCV] Add extra space into error message about unsupported extension version.

[MaskRay]

clang/test/Driver/riscv-arch.c

428

Nit: it's better to join 'zbt' (this compiler supports 0.93) to the previous line since it is one single message.

That's better than using -SAME: here, and in turn better than raw CHECK as is.

clang/test/Driver/riscv-arch.c

 // RUN: %clang --target=riscv32-unknown-elf -march=rv32izbt -menable-experimental-extensions -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-EXPERIMENTAL-NOVERS %s
 // RV32-EXPERIMENTAL-NOVERS: error: invalid arch name 'rv32izbt'
 // RV32-EXPERIMENTAL-NOVERS: experimental extension requires explicit version number
 
 // RUN: %clang --target=riscv32-unknown-elf -march=rv32izbt0p1 -menable-experimental-extensions -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-EXPERIMENTAL-BADVERS %s
 // RV32-EXPERIMENTAL-BADVERS: error: invalid arch name 'rv32izbt0p1'
 // RV32-EXPERIMENTAL-BADVERS: unsupported version number 0.1 for experimental extension
-// RV32-EXPERIMENTAL-BADVERS: 'zbt'(this compiler supports 0.93)
+// RV32-EXPERIMENTAL-BADVERS: 'zbt' (this compiler supports 0.93)
 
 // RUN: %clang --target=riscv32-unknown-elf -march=rv32izbt0p93 -menable-experimental-extensions -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-EXPERIMENTAL-GOODVERS %s
 // RV32-EXPERIMENTAL-GOODVERS: "-target-feature" "+experimental-zbt"
 
 // RUN: %clang --target=riscv32-unknown-elf -march=rv32izbb1p0 -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-ZBB %s
 // RUN: %clang --target=riscv32-unknown-elf -march=rv32izbb -### %s \

llvm/lib/Support/RISCVISAInfo.cpp

 //===-- RISCVISAInfo.cpp - RISCV Arch String Parser --------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
if (auto ExperimentalExtension = isExperimentalExtension(Ext)) {
 
     auto SupportedVers = *ExperimentalExtension;
     if (ExperimentalExtensionVersionCheck &&
         (Major != SupportedVers.Major || Minor != SupportedVers.Minor)) {
       std::string Error = "unsupported version number " + MajorStr.str();
       if (!MinorStr.empty())
         Error += "." + MinorStr.str();
       Error += " for experimental extension '" + Ext.str() +
-               "'(this compiler supports " + utostr(SupportedVers.Major) + "." +
-               utostr(SupportedVers.Minor) + ")";
+               "' (this compiler supports " + utostr(SupportedVers.Major) +
+               "." + utostr(SupportedVers.Minor) + ")";
       return createStringError(errc::invalid_argument, Error);
     }
     return Error::success();
   }
 
   // Exception rule for `g`, we don't have clear version scheme for that on
   // ISA spec.
   if (Ext == "g")