Improve the documentation.

src/ftxui/dom/composite_decorator.cpp

@@ -6,7 +6,7 @@
 namespace ftxui {
 
 /// @brief Center an element horizontally.
-/// @param The input element.
+/// @param child The decorated element.
 /// @return The centered element.
 /// @ingroup dom
 Element hcenter(Element child) {
@@ -14,7 +14,7 @@ Element hcenter(Element child) {
 }
 
 /// @brief Center an element vertically.
-/// @param The input element.
+/// @param child The decorated element.
 /// @return The centered element.
 /// @ingroup dom
 Element vcenter(Element child) {
@@ -22,7 +22,7 @@ Element vcenter(Element child) {
 }
 
 /// @brief Center an element horizontally and vertically.
-/// @param The input element.
+/// @param child The decorated element.
 /// @return The centered element.
 /// @ingroup dom
 Element center(Element child) {
@@ -30,7 +30,7 @@ Element center(Element child) {
 }
 
 /// @brief Align an element on the right side.
-/// @param The input element.
+/// @param child The decorated element.
 /// @return The right aligned element.
 /// @ingroup dom
 Element align_right(Element child) {

src/ftxui/dom/size.cpp

@@ -82,8 +82,8 @@ class Size : public Node {
 /// @brief Apply a constraint on the size of an element.
 /// @param direction Whether the WIDTH of the HEIGHT of the element must be
 ///                  constrained.
-/// @param constrain The type of constaint.
-/// @param value the value.
+/// @param constraint The type of constaint.
+/// @param value The value.
 /// @ingroup dom
 Decorator size(Direction direction, Constraint constraint, int value) {
   return [=](Element e) {

src/ftxui/dom/util.cpp

@@ -6,11 +6,13 @@
 
 namespace ftxui {
 
+namespace {
 Decorator compose(Decorator a, Decorator b) {
   return [a = std::move(a), b = std::move(b)](Element element) {
     return b(a(std::move(element)));
   };
 }
+}  // namespace
 
 /// @brief A decoration doing absolutely nothing.
 /// @ingroup dom