tests/test-issue612.t

templatekw: re-add showtags() to list tags keyword up in online help

Changeset d69a7fc68ad5 removed "showtags()" definition for "tags"
template keyword from "templatekw.py", because "namespaces" puts a
helper function for it into template keyword map automatically. This
works correctly from the point of view of templating functionality.

But on the other hand, it removed "tags" template keyword from "hg
help templates" unexpectedly, because online help text is built before
"namespaces" puts a helper function for "tags" into template keyword
map.

This patch is a kind of backing d69a7fc68ad5 out, but this implements
"showtags()" with newly introduced "shownames()" instead of originally
used "showlist()".

http://mercurial.selenic.com/bts/issue612

  $ hg init
  $ mkdir src
  $ echo a > src/a.c
  $ hg ci -Ama
  adding src/a.c

  $ hg mv src source
  moving src/a.c to source/a.c (glob)

  $ hg ci -Ammove

  $ hg co -C 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo new > src/a.c
  $ echo compiled > src/a.o
  $ hg ci -mupdate
  created new head

  $ hg status
  ? src/a.o

  $ hg merge
  merging src/a.c and source/a.c to source/a.c
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg status
  M source/a.c
  R src/a.c
  ? src/a.o