Add usage of std::move where compiler suggested

[torwig]

These warnings during the CI build with Clang should disappear.

/home/runner/work/kvrocks/kvrocks/src/config/config_type.h:167:27: warning: local variable 's' will be copied despite being returned by name [-Wreturn-std-move]
    if (!s.IsOK()) return s;
                          ^
/home/runner/work/kvrocks/kvrocks/src/config/config_type.h:167:27: note: call 'std::move' explicitly to avoid copying
    if (!s.IsOK()) return s;
                          ^
                          std::move(s)
1 warning generated.

Thanks to @aleksraiden for noticing.

[sonarcloud]

Quality Gate passed

Issues
0 New issues

Measures
0 Security Hotspots
60.8% Coverage on New Code
1.4% Duplication on New Code

See analysis details on SonarCloud