Revision selection: Couple minor clarifications and updates

Signed-off-by: Robert P. J. Day <[email protected]>

Author: robertpjday

book/07-git-tools/sections/revision-selection.asc

@@ -1,7 +1,7 @@
 [[_revision_selection]]
 === Revision Selection
 
-Git allows you to refer to a set of commits or a range of commits in several ways.
+Git allows you to refer to a single commit, set of commits, or range of commits in a number of ways.
 They aren't necessarily obvious but are helpful to know.
 
 ==== Single Revisions
@@ -60,7 +60,7 @@ a11bef0 first commit
 ----
 
 Generally, eight to ten characters are more than enough to be unique within a project.
-For example, as of June 2018, the Linux kernel (which is a fairly sizable project) has over 700,000 commits and almost six and a half million objects in its object database, with no two objects whose SHA-1s are identical in the first 11 characters.
+For example, as of February 2019, the Linux kernel (which is a fairly sizable project) has over 875,000 commits and almost seven million objects in its object database, with no two objects whose SHA-1s are identical in the first 12 characters.
 
 [NOTE]
 .A SHORT NOTE ABOUT SHA-1