fix: fix comment for new added files.

- translate zh-CN comment into en-US.
- change some comment into Doxygen style.
- add lost Doxygen comment.
- enrich the testbench for ceil_div.
- add lost metaprogramming functions for some files in macro namespace.

src/yycc/macro/stl_detector.hpp

@@ -12,3 +12,28 @@
 #else
 #error "Current STL is not supported!"
 #endif
+
+namespace yycc::macro::stl {
+
+    /// @brief The STL implementation kind.
+    enum class StlKind {
+        MSSTL,    ///< Microsoft STL
+        GNUSTL,   ///< GNU STL
+        CLANGSTL  ///< Clang STL
+    };
+
+    /**
+     * @brief Fetch the STL implementation
+     * @return The kind of STL implementation.
+     */
+    inline constexpr StlKind get_stl() {
+#if defined(YYCC_STL_MSSTL)
+        return StlKind::MSSTL;
+#elif defined(YYCC_STL_GNUSTL)
+        return StlKind::GNUSTL;
+#else
+        return StlKind::CLANGSTL;
+#endif
+    }
+
+} // namespace yycc::macro::stl