add fn comments for doxygen, rename OAMTile to OamTile

src/app/editor/context/gfx_context.h

@@ -19,7 +19,11 @@
 namespace yaze {
 namespace app {
 namespace editor {
+namespace context {
 
+/**
+ * @brief Shared graphical context across editors.
+ */
 class GfxContext {
  public:
   absl::Status Update();
@@ -29,6 +33,7 @@ class GfxContext {
   static std::unordered_map<uint8_t, gfx::Paletteset> palettesets_;
 };
 
+}  // namespace context
 }  // namespace editor
 }  // namespace app
 }  // namespace yaze