Reduce the header declarations (#1342)

- Since we have style rules to include foo.hpp at the top of its
  corresponding foo.cpp, this takes any headers included by foo.hpp
  as being also guaranteed for foo.cpp.

- Use C-style <foo.h> instead of <cfoo>, since the latter only
  guarantees putting symbols in the `std` namespace, which we are
  not using for C functions (e.g. `printf` not `std::printf`).

- Remove now-unused `__PRETTY_FUNCTION__` reporting

include/link/assign.hpp

@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: MIT */
 
-// Assigning all sections a place
 #ifndef RGBDS_LINK_ASSIGN_H
 #define RGBDS_LINK_ASSIGN_H
 

include/link/main.hpp

@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: MIT */
 
-// Declarations that all modules use, as well as `main` and related
 #ifndef RGBDS_LINK_MAIN_H
 #define RGBDS_LINK_MAIN_H
 

include/link/object.hpp

@@ -1,7 +1,5 @@
 /* SPDX-License-Identifier: MIT */
 
-// Declarations related to processing of object (.o) files
-
 #ifndef RGBDS_LINK_OBJECT_H
 #define RGBDS_LINK_OBJECT_H
 

include/link/output.hpp

@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: MIT */
 
-// Outputting the result of linking
 #ifndef RGBDS_LINK_OUTPUT_H
 #define RGBDS_LINK_OUTPUT_H
 

include/link/patch.hpp

@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: MIT */
 
-// Applying patches to SECTIONs
 #ifndef RGBDS_LINK_PATCH_H
 #define RGBDS_LINK_PATCH_H
 

include/link/sdas_obj.hpp

@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: MIT */
 
-// Assigning all sections a place
 #ifndef RGBDS_LINK_SDAS_OBJ_H
 #define RGBDS_LINK_SDAS_OBJ_H
 

include/link/section.hpp

@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: MIT */
 
-// Declarations manipulating symbols
 #ifndef RGBDS_LINK_SECTION_H
 #define RGBDS_LINK_SECTION_H
 

include/link/symbol.hpp

@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: MIT */
 
-// Declarations manipulating symbols
 #ifndef RGBDS_LINK_SYMBOL_H
 #define RGBDS_LINK_SYMBOL_H