refactor(build): remove INCLUDE_GENERATED_DECLARATIONS guards

These are not needed after #35129 but making uncrustify still play nice
with them was a bit tricky.

Unfortunately `uncrustify --update-config-with-doc` breaks strings
with backslashes. This issue has been reported upstream,
and in the meanwhile auto-update on every single run has been disabled.

src/nvim/log.c

@@ -37,9 +37,7 @@ static char log_file_path[MAXPATHL + 1] = { 0 };
 static bool did_log_init = false;
 static uv_mutex_t mutex;
 
-#ifdef INCLUDE_GENERATED_DECLARATIONS
-# include "log.c.generated.h"
-#endif
+#include "log.c.generated.h"
 
 #ifdef HAVE_EXECINFO_BACKTRACE
 # include <execinfo.h>