git-log.txt: include rev-list-description.txt

The `git log` synopsis mentions `<revision range>`, and the description
of this option links to gitrevisions(7), but a nice explanation of
how a revision range can be constructed from individual commits,
optionnally prefixed with `^`, also exists in `rev-list-description.txt`.

Include this description in the man page for `git log`.

Add Asciidoc 'ifdef's to `rev-list-description.txt` so that either `git
rev-list` or `git log` appears in the respective man pages.

Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: phil-blain

Documentation/git-log.txt

@@ -15,6 +15,9 @@ DESCRIPTION
 -----------
 Shows the commit logs.
 
+:git-log: 1
+include::rev-list-description.txt[]
+
 The command takes options applicable to the linkgit:git-rev-list[1]
 command to control what is shown and how, and options applicable to
 the linkgit:git-diff[1] command to control how the changes

Documentation/git-rev-list.txt

@@ -14,6 +14,7 @@ SYNOPSIS
 DESCRIPTION
 -----------
 
+:git-rev-list: 1
 include::rev-list-description.txt[]
 
 'rev-list' is a very essential Git command, since it

Documentation/rev-list-description.txt

@@ -12,9 +12,16 @@ result.
 
 Thus, the following command:
 
+ifdef::git-rev-list[]
 -----------------------------------------------------------------------
 $ git rev-list foo bar ^baz
 -----------------------------------------------------------------------
+endif::git-rev-list[]
+ifdef::git-log[]
+-----------------------------------------------------------------------
+$ git log foo bar ^baz
+-----------------------------------------------------------------------
+endif::git-log[]
 
 means "list all the commits which are reachable from 'foo' or 'bar', but
 not from 'baz'".
@@ -23,16 +30,32 @@ A special notation "'<commit1>'..'<commit2>'" can be used as a
 short-hand for "^'<commit1>' '<commit2>'". For example, either of
 the following may be used interchangeably:
 
+ifdef::git-rev-list[]
 -----------------------------------------------------------------------
 $ git rev-list origin..HEAD
 $ git rev-list HEAD ^origin
 -----------------------------------------------------------------------
+endif::git-rev-list[]
+ifdef::git-log[]
+-----------------------------------------------------------------------
+$ git log origin..HEAD
+$ git log HEAD ^origin
+-----------------------------------------------------------------------
+endif::git-log[]
 
 Another special notation is "'<commit1>'...'<commit2>'" which is useful
 for merges.  The resulting set of commits is the symmetric difference
 between the two operands.  The following two commands are equivalent:
 
+ifdef::git-rev-list[]
 -----------------------------------------------------------------------
 $ git rev-list A B --not $(git merge-base --all A B)
 $ git rev-list A...B
 -----------------------------------------------------------------------
+endif::git-rev-list[]
+ifdef::git-log[]
+-----------------------------------------------------------------------
+$ git log A B --not $(git merge-base --all A B)
+$ git log A...B
+-----------------------------------------------------------------------
+endif::git-log[]