tests/test-addremove.t

largefiles: improve comments, internal docstrings

- fix some ungrammatical/unclear/incorrect comments/docstrings
- rewrite some really unclear comments/docstrings
- make formatting/style more consistent with the rest of Mercurial
  (lowercase without period unless it's really multiple sentences)
- wrap to 75 columns
- always say "largefile(s)", not "lfile(s)" (or "big files")
- one space between sentences, not two

  $ hg init rep
  $ cd rep
  $ mkdir dir
  $ touch foo dir/bar
  $ hg -v addremove
  adding dir/bar
  adding foo
  $ hg -v commit -m "add 1"
  dir/bar
  foo
  committed changeset 0:6f7f953567a2
  $ cd dir/
  $ touch ../foo_2 bar_2 con.xml
  $ hg -v addremove
  adding dir/bar_2
  adding dir/con.xml
  adding foo_2
  warning: filename contains 'con', which is reserved on Windows: 'dir/con.xml'
  $ hg -v commit -m "add 2"
  dir/bar_2
  dir/con.xml
  foo_2
  committed changeset 1:6bb597da00f1

  $ cd ..
  $ hg init sim
  $ cd sim
  $ echo a > a
  $ echo a >> a
  $ echo a >> a
  $ echo c > c
  $ hg commit -Ama
  adding a
  adding c
  $ mv a b
  $ rm c
  $ echo d > d
  $ hg addremove -n -s 50 # issue 1696
  removing a
  adding b
  removing c
  adding d
  recording removal of a as rename to b (100% similar)
  $ hg addremove -s 50
  removing a
  adding b
  removing c
  adding d
  recording removal of a as rename to b (100% similar)
  $ hg commit -mb