test-command-template: test 'children' template keyword

tests/test-command-template

@@ -125,6 +125,7 b" hg log --template '{date|rfc822date}\\n'"
 hg log --template '{desc|firstline}\n'
 hg log --template '{node|short}\n'
 hg log --template '<changeset author="{author|xmlescape}"/>\n'
+hg log --template '{rev}: {children}\n'
 
 echo '# formatnode filter works'
 echo '#  quiet'

tests/test-command-template.out

@@ -1018,6 +1018,15 b' 1e4e1b8f71e0'
 <changeset author="other@place"/>
 <changeset author="A. N. Other &lt;other@place&gt;"/>
 <changeset author="User Name &lt;user@hostname&gt;"/>
+8: 
+7: 8:95c24699272e
+6: 
+5: 6:c7b487c6c50e
+4: 6:c7b487c6c50e
+3: 4:32a18f097fcc 5:13207e5a10d9
+2: 3:10e46f2dcbf4
+1: 2:97054abb4ab8
+0: 1:b608e9d1a3f0
 # formatnode filter works
 #  quiet
 1e4e1b8f71e0