tests/test-eol-add.t

typing: attempt to remove @overloads in the platform module for stdlib methods

This is mostly successful, as examining util.pyi, posix.pyi, and windows.pyi
after a pytype run shows that the type overloads for `oslink`, `readlink`,
`removedirs`, `rename`, `split`, and `unlink` have been removed.  (Some of these
still have an @overload, but the differences are the variable names, not the
types.)  However, @overloads remain for `abspath` and `normpath` for some
reason.

It's useful to redefine these methods for the type checking phase because in
addition to excluding str and PathLike variants, some of these functions have
optional args in stdlib that aren't implemented in the custom implementation on
Windows, and we want the type checking to flag that instead of assuming it's an
allowable overload everywhere.

One last quirk I noticed that I can't explain- `pycompat.TYPE_CHECKING` is
always False, so the conditionals need to check `typing.TYPE_CHECKING` directly.
I tried dropping the custom code for assigning `pycompat.TYPE_CHECKING` and
simply did `from typing import TYPE_CHECKING` directly in pycompat.py, and used
`pycompat.TYPE_CHECKING` for the conditional here... and pytype complained that
`pycompat` doesn't have the `TYPE_CHECKING` variable.

Test adding .hgeol

  $ cat >> $HGRCPATH <<EOF
  > [diff]
  > git = 1
  > EOF
  $ seteol () {
  >     if [ $1 = "LF" ]; then
  >         EOL='\n'
  >     else
  >         EOL='\r\n'
  >     fi
  > }
  $ makerepo () {
  >     echo
  >     echo "# ==== setup repository ===="
  >     echo '% hg init'
  >     hg init repo
  >     cd repo
  >     printf "first\nsecond\nthird\n" > a.txt
  >     hg commit -d '100 0' --addremove -m 'LF commit'
  >     cd ..
  > }
  $ dotest () {
  >     seteol $1
  >     echo
  >     echo "% hg clone repo repo-$1"
  >     hg clone repo repo-$1
  >     cd repo-$1
  >     cat > .hg/hgrc <<EOF
  > [extensions]
  > eol =
  > [eol]
  > native = LF
  > EOF
  >     cat > .hgeol <<EOF
  > [patterns]
  > **.txt = native
  > [repository]
  > native = $1
  > EOF
  >     echo '% hg add .hgeol'
  >     hg add .hgeol
  >     echo '% hg status'
  >     hg status
  >     echo '% hg commit'
  >     hg commit -d '200 0' -m 'Added .hgeol file'
  >     echo '% hg status'
  >     hg status
  >     echo '% hg tip -p'
  >     hg tip -p
  >     cd ..
  >     rm -r repo-$1
  > }
  $ makerepo
  
  # ==== setup repository ====
  % hg init
  adding a.txt
  $ dotest LF
  
  % hg clone repo repo-LF
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  % hg add .hgeol
  % hg status
  A .hgeol
  % hg commit
  % hg status
  % hg tip -p
  changeset:   1:33503edb53b0
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:03:20 1970 +0000
  summary:     Added .hgeol file
  
  diff --git a/.hgeol b/.hgeol
  new file mode 100644
  --- /dev/null
  +++ b/.hgeol
  @@ -0,0 +1,4 @@
  +[patterns]
  +**.txt = native
  +[repository]
  +native = LF
  
  $ dotest CRLF
  
  % hg clone repo repo-CRLF
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  % hg add .hgeol
  % hg status
  M a.txt
  A .hgeol
  % hg commit
  % hg status
  % hg tip -p
  changeset:   1:6e64eaa9eb23
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:03:20 1970 +0000
  summary:     Added .hgeol file
  
  diff --git a/.hgeol b/.hgeol
  new file mode 100644
  --- /dev/null
  +++ b/.hgeol
  @@ -0,0 +1,4 @@
  +[patterns]
  +**.txt = native
  +[repository]
  +native = CRLF
  diff --git a/a.txt b/a.txt
  --- a/a.txt
  +++ b/a.txt
  @@ -1,3 +1,3 @@
  -first
  -second
  -third
  +first\r (esc)
  +second\r (esc)
  +third\r (esc)
  
  $ rm -r repo