Driver.cpp: add space in color-diagnostics description #1552

Job	Run time
bindings	18m 13s
conan	6m 37s
linux-coverage	12m 21s
build (clang-sanitize, ubuntu-22.04)	34m 32s
build (gcc-release, ubuntu-22.04)	7m 35s
build (gcc-11-release, ubuntu-22.04)	8m 1s
build (gcc-debug-shared, ubuntu-22.04)	6m 41s
build (gcc-debug-noexcept, ubuntu-22.04)	7m 13s
build (macos-release, macos-13)	5m 19s
build (win64-release, windows-latest)	9m 59s
build (win64-debug-shared, windows-latest)	8m 10s
build (win64-debug-noexcept, windows-latest)	7m 27s
	2h 12m 8s

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