patch 8.0.0601: no test coverage for :spellrepall

Problem:    No test coverage for :spellrepall.
Solution:   Add a test. (Dominique Pelle, closes #1717)

src/testdir/test_spell.vim

@@ -27,3 +27,20 @@ func Test_z_equal_on_invalid_utf8_word()
   set nospell
   bwipe!
 endfunc
+
+func Test_spellreall()
+  new
+  set spell
+  call assert_fails('spellrepall', 'E752:')
+  call setline(1, ['A speling mistake. The same speling mistake.',
+  \                'Another speling mistake.'])
+  call feedkeys(']s1z=', 'tx')
+  call assert_equal('A spelling mistake. The same speling mistake.', getline(1))
+  call assert_equal('Another speling mistake.', getline(2))
+  spellrepall
+  call assert_equal('A spelling mistake. The same spelling mistake.', getline(1))
+  call assert_equal('Another spelling mistake.', getline(2))
+  call assert_fails('spellrepall', 'E753:')
+  set spell&
+  bwipe!
+endfunc

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    601,
 /**/
     600,
 /**/