[core] Fix modernize-pass-by-value errors in header files

As reported by clang-tidy-8.

src/mbgl/geometry/anchor.hpp

@@ -2,7 +2,7 @@
 
 #include <mbgl/util/geometry.hpp>
 #include <mbgl/util/optional.hpp>
-
+#include <utility>
 #include <vector>
 
 namespace mbgl {
@@ -14,7 +14,7 @@ public:
     optional<std::size_t> segment;
 
     Anchor(float x_, float y_, float angle_, optional<std::size_t> segment_ = nullopt)
-        : point(x_, y_), angle(angle_), segment(segment_) {}
+        : point(x_, y_), angle(angle_), segment(std::move(segment_)) {}
 };
 
 using Anchors = std::vector<Anchor>;

src/mbgl/renderer/render_tree.hpp

@@ -5,6 +5,7 @@
 #include <cassert>
 #include <memory>
 #include <string>
+#include <utility>
 #include <vector>
 
 namespace mbgl {
@@ -29,18 +30,16 @@ using RenderItems = std::vector<std::reference_wrapper<const RenderItem>>;
 
 class RenderTreeParameters {
 public:
-    explicit RenderTreeParameters(
-        const TransformState& state_,
-        MapMode mapMode_,
-        MapDebugOptions debugOptions_,
-        TimePoint timePoint_,
-        const EvaluatedLight& light_)
+    explicit RenderTreeParameters(const TransformState& state_,
+                                  MapMode mapMode_,
+                                  MapDebugOptions debugOptions_,
+                                  TimePoint timePoint_,
+                                  EvaluatedLight light_)
         : transformParams(state_),
           mapMode(mapMode_),
           debugOptions(debugOptions_),
           timePoint(timePoint_),
-          light(light_) {
-    }
+          light(std::move(light_)) {}
     TransformParameters transformParams;
     MapMode mapMode;
     MapDebugOptions debugOptions;

src/mbgl/text/shaping.hpp

@@ -7,6 +7,8 @@
 #include <mbgl/text/glyph_atlas.hpp>
 #include <mbgl/text/tagged_string.hpp>
 
+#include <utility>
+
 namespace mbgl {
 
 struct AnchorAlignment {
@@ -44,7 +46,7 @@ class PositionedIcon {
 private:
     PositionedIcon(
         ImagePosition image_, float top_, float bottom_, float left_, float right_, const Padding& collisionPadding_)
-        : _image(image_),
+        : _image(std::move(image_)),
           _top(top_),
           _bottom(bottom_),
           _left(left_),