rev-list-options: fix off-by-one in '--filter=blob:limit=<n>' explainer

'--filter=blob:limit=<n>' was introduced in 25ec7bcac0 (list-objects:
filter objects in traverse_commit_list, 2017-11-21) and later expanded
to bitmaps in 84243da129 (pack-bitmap: implement BLOB_LIMIT filtering,
2020-02-14)

The logic that was introduced in these commits (and that still persists
to this day) omits blobs larger than _or equal_ to n bytes or units.

However, the documentation (Documentation/rev-list-options.txt) states:

>The form '--filter=blob:limit=<n>[kmg]' omits blobs larger than n
bytes or units. n may be zero.

Moreover, the t6113-rev-list-bitmap-filters.sh tests for exactly this
logic, so it seems it is the documentation that needs fixing, not the
code.

This changes the explanation to be similar to
Documentation/git-clone.txt, which is correct.

Signed-off-by: Nikolay Edigaryev <edigaryev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/rev-list-options.txt

@@ -927,10 +927,10 @@ ifdef::git-rev-list[]
 +
 The form '--filter=blob:none' omits all blobs.
 +
-The form '--filter=blob:limit=<n>[kmg]' omits blobs larger than n bytes
-or units.  n may be zero.  The suffixes k, m, and g can be used to name
-units in KiB, MiB, or GiB.  For example, 'blob:limit=1k' is the same
-as 'blob:limit=1024'.
+The form '--filter=blob:limit=<n>[kmg]' omits blobs of size at least n
+bytes or units.  n may be zero.  The suffixes k, m, and g can be used
+to name units in KiB, MiB, or GiB.  For example, 'blob:limit=1k'
+is the same as 'blob:limit=1024'.
 +
 The form '--filter=object:type=(tag|commit|tree|blob)' omits all objects
 which are not of the requested type.