record: fix revert -i for lines without newline (issue5651)

This is a regression caused by 66117dae87f9. Code prior to 66117dae87f9
seems to miss the "\ No newline at end of file" line.

Differential Revision: https://phab.mercurial-scm.org/D528

mercurial/patch.py

@@ -972,7 +972,7 b' class recordhunk(object):'
         that, swap fromline/toline and +/- signs while keep other things
         unchanged.
         """
-        m = {'+': '-', '-': '+'}
+        m = {'+': '-', '-': '+', '\\': '\\'}
         hunk = ['%s%s' % (m[l[0]], l[1:]) for l in self.hunk]
         return recordhunk(self.header, self.toline, self.fromline, self.proc,
                           self.before, hunk, self.after)

tests/test-revert-interactive.t

@@ -460,3 +460,40 b' Check the experimental config to invert '
   forget added file newfile (Yn)? y
   $ hg status
   ? newfile
+
+When a line without EOL is selected during "revert -i" (issue5651)
+
+  $ cat <<EOF >> $HGRCPATH
+  > [experimental]
+  > %unset revertalternateinteractivemode
+  > EOF
+
+  $ hg init $TESTTMP/revert-i-eol
+  $ cd $TESTTMP/revert-i-eol
+  $ echo 0 > a
+  $ hg ci -qAm 0
+  $ printf 1 >> a
+  $ hg ci -qAm 1
+  $ cat a
+  0
+  1 (no-eol)
+
+  $ hg revert -ir'.^' <<EOF
+  > y
+  > y
+  > EOF
+  reverting a
+  diff --git a/a b/a
+  1 hunks, 1 lines changed
+  examine changes to 'a'? [Ynesfdaq?] y
+  
+  @@ -1,1 +1,2 @@
+   0
+  +1
+  \ No newline at end of file
+  revert this change to 'a'? [Ynesfdaq?] y
+  
+  $ cat a
+  0
+
+  $ cd ..