[core] Fix modernize-use-override errors in header files

As reported by clang-tidy-8.

include/mbgl/style/expression/number_format.hpp

@@ -15,7 +15,7 @@ public:
                  std::unique_ptr<Expression> minFractionDigits_,
                  std::unique_ptr<Expression> maxFractionDigits_);
 
-    ~NumberFormat();
+    ~NumberFormat() override;
 
     static ParseResult parse(const mbgl::style::conversion::Convertible& value, ParsingContext& ctx);
 

include/mbgl/style/layers/background_layer.hpp

@@ -17,7 +17,7 @@ class TransitionOptions;
 class BackgroundLayer final : public Layer {
 public:
     BackgroundLayer(const std::string& layerID);
-    ~BackgroundLayer() final;
+    ~BackgroundLayer() override;
 
     // Paint properties
 

include/mbgl/style/layers/circle_layer.hpp

@@ -17,7 +17,7 @@ class TransitionOptions;
 class CircleLayer final : public Layer {
 public:
     CircleLayer(const std::string& layerID, const std::string& sourceID);
-    ~CircleLayer() final;
+    ~CircleLayer() override;
 
     // Layout properties
 

include/mbgl/style/layers/fill_extrusion_layer.hpp

@@ -17,7 +17,7 @@ class TransitionOptions;
 class FillExtrusionLayer final : public Layer {
 public:
     FillExtrusionLayer(const std::string& layerID, const std::string& sourceID);
-    ~FillExtrusionLayer() final;
+    ~FillExtrusionLayer() override;
 
     // Paint properties
 

include/mbgl/style/layers/fill_layer.hpp

@@ -17,7 +17,7 @@ class TransitionOptions;
 class FillLayer final : public Layer {
 public:
     FillLayer(const std::string& layerID, const std::string& sourceID);
-    ~FillLayer() final;
+    ~FillLayer() override;
 
     // Layout properties
 

include/mbgl/style/layers/heatmap_layer.hpp

@@ -18,7 +18,7 @@ class TransitionOptions;
 class HeatmapLayer final : public Layer {
 public:
     HeatmapLayer(const std::string& layerID, const std::string& sourceID);
-    ~HeatmapLayer() final;
+    ~HeatmapLayer() override;
 
     // Paint properties
 

include/mbgl/style/layers/hillshade_layer.hpp

@@ -17,7 +17,7 @@ class TransitionOptions;
 class HillshadeLayer final : public Layer {
 public:
     HillshadeLayer(const std::string& layerID, const std::string& sourceID);
-    ~HillshadeLayer() final;
+    ~HillshadeLayer() override;
 
     // Paint properties
 

include/mbgl/style/layers/layer.hpp.ejs

@@ -39,7 +39,7 @@ public:
 <% } else { -%>
     <%- camelize(type) %>Layer(const std::string& layerID, const std::string& sourceID);
 <% } -%>
-    ~<%- camelize(type) %>Layer() final;
+    ~<%- camelize(type) %>Layer() override;
 
 <% if (layoutProperties.length) { -%>
     // Layout properties

include/mbgl/style/layers/line_layer.hpp

@@ -20,7 +20,7 @@ class TransitionOptions;
 class LineLayer final : public Layer {
 public:
     LineLayer(const std::string& layerID, const std::string& sourceID);
-    ~LineLayer() final;
+    ~LineLayer() override;
 
     // Layout properties
 

include/mbgl/style/layers/location_indicator_layer.hpp

@@ -18,7 +18,7 @@ class TransitionOptions;
 class LocationIndicatorLayer final : public Layer {
 public:
     LocationIndicatorLayer(const std::string& layerID);
-    ~LocationIndicatorLayer();
+    ~LocationIndicatorLayer() override;
 
     // Layout properties
 

include/mbgl/style/layers/raster_layer.hpp

@@ -17,7 +17,7 @@ class TransitionOptions;
 class RasterLayer final : public Layer {
 public:
     RasterLayer(const std::string& layerID, const std::string& sourceID);
-    ~RasterLayer() final;
+    ~RasterLayer() override;
 
     // Paint properties
 

include/mbgl/style/layers/symbol_layer.hpp

@@ -20,7 +20,7 @@ class TransitionOptions;
 class SymbolLayer final : public Layer {
 public:
     SymbolLayer(const std::string& layerID, const std::string& sourceID);
-    ~SymbolLayer() final;
+    ~SymbolLayer() override;
 
     // Layout properties
 

src/mbgl/gfx/offscreen_texture.hpp

@@ -15,7 +15,7 @@ protected:
     }
 
 public:
-    virtual ~OffscreenTexture() = default;
+    ~OffscreenTexture() override = default;
 
     virtual bool isRenderable() = 0;
 

src/mbgl/gl/index_buffer_resource.hpp

@@ -9,7 +9,7 @@ namespace gl {
 class IndexBufferResource : public gfx::IndexBufferResource {
 public:
     IndexBufferResource(UniqueBuffer&& buffer_, int byteSize_) : buffer(std::move(buffer_)), byteSize(byteSize_) {}
-    ~IndexBufferResource();
+    ~IndexBufferResource() override;
 
     UniqueBuffer buffer;
     int byteSize;

src/mbgl/gl/texture_resource.hpp

@@ -9,7 +9,7 @@ namespace gl {
 class TextureResource : public gfx::TextureResource {
 public:
     TextureResource(UniqueTexture&& texture_, int byteSize_) : texture(std::move(texture_)), byteSize(byteSize_) {}
-    ~TextureResource();
+    ~TextureResource() override;
 
     static int getStorageSize(const Size& size, gfx::TexturePixelType format, gfx::TextureChannelDataType type);
 

src/mbgl/gl/vertex_buffer_resource.hpp

@@ -9,7 +9,7 @@ namespace gl {
 class VertexBufferResource : public gfx::VertexBufferResource {
 public:
     VertexBufferResource(UniqueBuffer&& buffer_, int byteSize_) : buffer(std::move(buffer_)), byteSize(byteSize_) {}
-    ~VertexBufferResource();
+    ~VertexBufferResource() override;
 
     UniqueBuffer buffer;
     int byteSize;

src/mbgl/renderer/render_source.hpp

@@ -48,7 +48,7 @@ using RenderTiles = std::shared_ptr<const std::vector<std::reference_wrapper<con
 class RenderSource : protected TileObserver {
 public:
     static std::unique_ptr<RenderSource> create(const Immutable<style::Source::Impl>&);
-    virtual ~RenderSource();
+    ~RenderSource() override;
 
     bool isEnabled() const;
     virtual bool isLoaded() const = 0;