patchpack-revindex.h: fix typos of time complexity

> From: kylezhao <kylezhao@tencent.com>
> 
> Signed-off-by: kylezhao <kylezhao@tencent.com>
> ---
>      pack-revindex.h: fix typos of time complexity
>      
>      It looks like the time complexity descriptions were written wrong.
>      
>      Regards, Kyle
> 
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1039%2Fkeyu98%2Fkz%2Ffix-pack-revindex-typo-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1039/keyu98/kz/fix-pack-revindex-typo-v1
> Pull-Request: https://github.com/gitgitgadget/git/pull/1039
> 
>   pack-revindex.h | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/pack-revindex.h b/pack-revindex.h
> index 479b8f2f9c9..74f4eae668d 100644
> --- a/pack-revindex.h
> +++ b/pack-revindex.h
> @@ -109,7 +109,7 @@ off_t pack_pos_to_offset(struct packed_git *p, uint32_t pos);
>    * If the reverse index has not yet been loaded, or the position is out of
>    * bounds, this function aborts.
>    *
> - * This function runs in time O(log N) with the number of objects in the MIDX.
> + * This function runs in constant time.
>    */
>   uint32_t pack_pos_to_midx(struct multi_pack_index *m, uint32_t pos);
>   
> @@ -120,7 +120,7 @@ uint32_t pack_pos_to_midx(struct multi_pack_index *m, uint32_t pos);
>    * If the reverse index has not yet been loaded, or the position is out of
>    * bounds, this function aborts.
>    *
> - * This function runs in constant time.
> + * This function runs in time O(log N) with the number of objects in the MIDX.
>    */
>   int midx_to_pack_pos(struct multi_pack_index *midx, uint32_t at, uint32_t *pos);
>   
> 
> base-commit: 8b7c11b8668b4e774f81a9f0b4c30144b818f1d1
> 

> From: kylezhao <kylezhao@tencent.com>
> 
> Time complexities for pack_pos_to_midx and midx_to_pack_pos are swapped,
> correct it.
> 
> Signed-off-by: kylezhao <kylezhao@tencent.com>
> ---

>   pack-revindex.h | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/pack-revindex.h b/pack-revindex.h
> index 479b8f2f9c9..74f4eae668d 100644
> --- a/pack-revindex.h
> +++ b/pack-revindex.h
> @@ -109,7 +109,7 @@ off_t pack_pos_to_offset(struct packed_git *p, uint32_t pos);
>    * If the reverse index has not yet been loaded, or the position is out of
>    * bounds, this function aborts.
>    *
> - * This function runs in time O(log N) with the number of objects in the MIDX.
> + * This function runs in constant time.
>    */
>   uint32_t pack_pos_to_midx(struct multi_pack_index *m, uint32_t pos);
>   
> @@ -120,7 +120,7 @@ uint32_t pack_pos_to_midx(struct multi_pack_index *m, uint32_t pos);
>    * If the reverse index has not yet been loaded, or the position is out of
>    * bounds, this function aborts.
>    *
> - * This function runs in constant time.
> + * This function runs in time O(log N) with the number of objects in the MIDX.
>    */
>   int midx_to_pack_pos(struct multi_pack_index *midx, uint32_t at, uint32_t *pos);
>   
> 
> base-commit: 8b7c11b8668b4e774f81a9f0b4c30144b818f1d1
> 

> But these two were swapped, and are now correct after your patch. Thanks
> again.
>
>     Reviewed-by: Taylor Blau <me@ttaylorr.com>
>
> Thanks,
> Taylor