add TODOs in function implementations.

Author: vonosmas

libc/src/nl_types/catclose.cpp

@@ -14,7 +14,8 @@
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(int, catclose, ([[maybe_unused]] nl_catd catalog)) {
-  // Message catalogs are not implemented. Return error regardless of input.
+  // TODO: Add implementation for message catalogs. For now, return error
+  // regardless of input.
   return -1;
 }
 

libc/src/nl_types/catgets.cpp

@@ -17,8 +17,8 @@ LLVM_LIBC_FUNCTION(char *, catgets,
                    ([[maybe_unused]] nl_catd catalog,
                     [[maybe_unused]] int set_number,
                     [[maybe_unused]] int message_number, const char *message)) {
-  // Message catalogs are not implemented.
-  // Return backup message regardless of input.
+  // TODO: Add implementation for message catalogs. For now, return backup
+  // message regardless of input.
   return const_cast<char *>(message);
 }
 

libc/src/nl_types/catopen.cpp

@@ -17,7 +17,8 @@ namespace LIBC_NAMESPACE_DECL {
 LLVM_LIBC_FUNCTION(nl_catd, catopen,
                    ([[maybe_unused]] const char *name,
                     [[maybe_unused]] int flag)) {
-  // Message catalogs are not implemented. Return error regardless of input.
+  // TODO: Add implementation for message catalogs. For now, return error
+  // regardless of input.
   libc_errno = EINVAL;
   return reinterpret_cast<nl_catd>(-1);
 }