[msvc][fix] msvc needs explicit namespace for some using-declarations

test/static/dimension_test.cpp

@@ -33,7 +33,7 @@ namespace {
 
 using namespace mp_units;
 
-using dimension_one_ = struct dimension_one;
+using dimension_one_ = struct mp_units::dimension_one;
 
 // clang-format off
 inline constexpr struct length_ final : base_dimension<"L"> {} length;

test/static/quantity_spec_test.cpp

@@ -33,8 +33,8 @@ namespace {
 
 using namespace mp_units;
 
-using dimensionless_ = struct dimensionless;
-using dim_one_ = struct dimension_one;
+using dimensionless_ = struct mp_units::dimensionless;
+using dim_one_ = struct mp_units::dimension_one;
 
 // clang-format off
 inline constexpr struct dim_length_ final : base_dimension<"L"> {} dim_length;

test/static/reference_test.cpp

@@ -34,8 +34,8 @@ namespace {
 
 using namespace mp_units;
 
-using dimensionless_ = struct dimensionless;
-using one_ = struct one;
+using dimensionless_ = struct mp_units::dimensionless;
+using one_ = struct mp_units::one;
 
 // base dimensions
 // clang-format off

test/static/unit_test.cpp

@@ -35,8 +35,8 @@ namespace {
 using namespace mp_units;
 using namespace mp_units::detail;
 
-using one_ = struct one;
-using percent_ = struct percent;
+using one_ = struct mp_units::one;
+using percent_ = struct mp_units::percent;
 
 // base dimensions
 // clang-format off