patch 9.1.1319: Various typos in the code, issue with test_inst_complete.vim

Problem:  Various typos in the code, redundant and strange use of
          :execute in test_ins_complete.vim (after 9.1.1315).
Solution: Fix typos in the code and in the documentation, use the
          executed command directly (zeertzjq).

closes: #17143

Co-authored-by: Christ van Willegen <cvwillegen@gmail.com>
Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_ins_complete.vim b/src/testdir/test_ins_complete.vim
index 916ad19..9d39b2a 100644
--- a/src/testdir/test_ins_complete.vim
+++ b/src/testdir/test_ins_complete.vim
@@ -3598,7 +3598,7 @@
   call feedkeys("Gofuzzy\<C-X>\<C-N>\<C-N>\<C-N>\<C-Y>\<Esc>0", 'tx!')
   call assert_equal('completefuzzycollect', getline('.'))
 
-  execute('%d _')
+  %d _
   call setline(1, ['fuzzy', 'fuzzy foo', "fuzzy bar", 'fuzzycollect'])
   call feedkeys("Gofuzzy\<C-X>\<C-N>\<C-N>\<C-N>\<C-Y>\<Esc>0", 'tx!')
   call assert_equal('fuzzycollect', getline('.'))