clean up shell scripts for shellcheck linter checks

meson.build

meson/bash_ninja_autocomplete.sh

meson/c_main_sourcefiles.sh

meson/check_binary_grid2.sh

meson/clean_data_objects.sh

meson/cpu_frequency.sh

meson/data_object_list.sh

meson/data_object_list_and_build.sh

meson/git_revision.sh

meson/list_shared_symbols.sh

meson/pgo.sh

tbse