patch 8.2.4510: Vim9: shortening commands leads to confusing script

Problem:    Vim9: shortening commands leads to confusing script.
Solution:   In Vim9 script require at least ":cont" for ":continue", "const"
            instead of "cons", "break" instead of "brea", "catch" instead of
            "cat", "else" instead of "el" "elseif" instead of "elsei" "endfor"
            instead of "endfo" "endif" instead of "en" "endtry" instead of
            "endt", "finally" instead of "fina", "throw" instead of "th",
            "while" instead of "wh".
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index f60fb36..a503d11 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -460,7 +460,7 @@
     endtry
   catch /wrong/
     add(l, 'caught')
-  fina
+  finally
     add(l, 'finally')
   endtry
   assert_equal(['1', 'caught', 'finally'], l)
@@ -1004,7 +1004,7 @@
 def s:ReturnFinally(): string
   try
     return 'intry'
-  finall
+  finally
     g:in_finally = 'finally'
   endtry
   return 'end'
@@ -3374,6 +3374,37 @@
   g:StopVimInTerminal(buf)
 enddef
 
+def Test_minimal_command_name_length()
+  var names = [
+       'cons',
+       'brea',
+       'cat',
+       'catc',
+       'con',
+       'el',
+       'els',
+       'elsei',
+       'endfo',
+       'en',
+       'end',
+       'endi',
+       'endw',
+       'endt',
+       'endtr',
+       'fina',
+       'finall',
+       'th',
+       'thr',
+       'thro',
+       'wh',
+       'whi',
+       'whil',
+      ]
+  for name in names
+    v9.CheckDefAndScriptFailure([name .. ' '], 'E1065:')
+  endfor
+enddef
+
 def Test_unset_any_variable()
   var lines =<< trim END
     var name: any