Apply more clang-tidy fixes (#2763)

include/mbgl/gfx/shader_group.hpp

@@ -130,8 +130,10 @@ public:
     /// @tparam T Derived type, inheriting `gfx::Shader`
     /// @param to Location to store the shader
     /// @return True if 'to' has a valid program object, false otherwise.
-    template <typename T, typename std::enable_if_t<is_shader_v<T>, bool>* = nullptr>
-    bool populate(std::shared_ptr<T>& to) noexcept {
+    template <typename T>
+    bool populate(std::shared_ptr<T>& to) noexcept
+        requires(is_shader_v<T>)
+    {
         if (to) {
             return true;
         }

include/mbgl/gfx/vertex_attribute.hpp

@@ -191,12 +191,15 @@ public:
     }
 
     template <std::size_t I = 0, typename... Tp>
-    inline typename std::enable_if_t<I == sizeof...(Tp), void> set(std::size_t, std::tuple<Tp...>, std::size_t) {}
+    inline void set(std::size_t, std::tuple<Tp...>, std::size_t)
+        requires(I == sizeof...(Tp))
+    {}
 
     /// Set item value
     template <std::size_t I = 0, typename... Tp>
-        inline typename std::enable_if_t <
-        I<sizeof...(Tp), void> set(std::size_t i, std::tuple<Tp...> tuple, std::size_t tupleIndex) {
+    inline void set(std::size_t i, std::tuple<Tp...> tuple, std::size_t tupleIndex)
+        requires(I < sizeof...(Tp))
+    {
         if (tupleIndex == 0) {
             set(i, std::get<I>(tuple).a1);
         } else {

include/mbgl/util/string.hpp

@@ -50,6 +50,8 @@ inline std::string toString(uint8_t t) {
     return toString(static_cast<uint32_t>(t));
 }
 
+// NOLINTBEGIN(bugprone-incorrect-enable-if)
+
 template <typename = std::enable_if<!std::is_same_v<uint64_t, unsigned long>>>
 inline std::string toString(unsigned long t) {
     return toString(static_cast<uint64_t>(t));
@@ -70,6 +72,8 @@ inline std::string toString(long long t) {
     return toString(static_cast<int64_t>(t));
 }
 
+// NOLINTEND(bugprone-incorrect-enable-if)
+
 inline std::string toString(float t, bool decimal = false) {
     return toString(static_cast<double>(t), decimal);
 }