API typo: replace "catagory" with "category"

[kshtsk]

> grep -ri catagory .
./utils/qzip.h:typedef struct QzCatagory_S {
./utils/qzip.h:} QzCatagory_T;
./utils/qzip.h:typedef struct QzCatagoryTable_S {
./utils/qzip.h:    QzCatagory_T     *catas; /* array: catas[cat_num] */
./utils/qzip.h:} QzCatagoryTable_T;
./utils/qzip.h:    QzCatagoryTable_T  *table;
./utils/qzip.h:QzCatagoryTable_T *createCatagoryList();
./utils/qzip.h:int scanFilesIntoCatagory(Qz7zItemList_T *the_list);
./utils/qzip_7z.c:    QzCatagoryTable_T *table = p->table;
./utils/qzip_7z.c:    QzCatagory_T      cat;
./utils/qzip_7z.c:        QzCatagory_T *cat = &(the_list->table->catas[i]);
./utils/qzip_7z.c:QzCatagoryTable_T *createCatagoryList()
./utils/qzip_7z.c:    QzCatagoryTable_T  *cat_tbl;
./utils/qzip_7z.c:    cat_tbl = malloc(sizeof(QzCatagoryTable_T));
./utils/qzip_7z.c:    cat_tbl->catas = malloc(cat_tbl->cat_num * sizeof(QzCatagory_T));
./utils/qzip_7z.c:int getCatagory(QzCatagoryTable_T *tbl, Qz7zFileItem_T *p)
./utils/qzip_7z.c:int scanFilesIntoCatagory(Qz7zItemList_T *the_list)
./utils/qzip_7z.c:    QzCatagory_T *cat = the_list->table->catas;
./utils/qzip_7z.c:        cat_index = getCatagory(the_list->table, p);
./utils/qzip_7z.c:    res->table = createCatagoryList();
./utils/qzip_7z.c:    scanFilesIntoCatagory(res);

Unfortunate typo has been found in the code.