patch 8.2.2805: Vim9: cannot use legacy syntax in Vim9 script

Problem:    Vim9: cannot use legacy syntax in Vim9 script.
Solution:   Add the :legacy command.
diff --git a/src/ex_cmdidxs.h b/src/ex_cmdidxs.h
index 70fb71a..0d148d7 100644
--- a/src/ex_cmdidxs.h
+++ b/src/ex_cmdidxs.h
@@ -17,20 +17,20 @@
   /* j */ 209,
   /* k */ 211,
   /* l */ 216,
-  /* m */ 278,
-  /* n */ 296,
-  /* o */ 316,
-  /* p */ 328,
-  /* q */ 367,
-  /* r */ 370,
-  /* s */ 390,
-  /* t */ 459,
-  /* u */ 504,
-  /* v */ 515,
-  /* w */ 536,
-  /* x */ 550,
-  /* y */ 560,
-  /* z */ 561
+  /* m */ 279,
+  /* n */ 297,
+  /* o */ 317,
+  /* p */ 329,
+  /* q */ 368,
+  /* r */ 371,
+  /* s */ 391,
+  /* t */ 460,
+  /* u */ 505,
+  /* v */ 516,
+  /* w */ 537,
+  /* x */ 551,
+  /* y */ 561,
+  /* z */ 562
 };
 
 /*
@@ -52,7 +52,7 @@
   /* i */ {  1,  0,  0,  0,  0,  3,  0,  0,  0,  4,  0,  5,  6,  0,  0,  0,  0,  0, 14,  0, 16,  0,  0,  0,  0,  0 },
   /* j */ {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  1,  0,  0,  0,  0,  0 },
   /* k */ {  0,  0,  0,  0,  1,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0 },
-  /* l */ {  3, 11, 15, 19, 20, 24, 27, 32,  0,  0,  0, 34, 37, 40, 44, 50,  0, 52, 61, 53, 54, 58, 60,  0,  0,  0 },
+  /* l */ {  3, 11, 15, 19, 20, 25, 28, 33,  0,  0,  0, 35, 38, 41, 45, 51,  0, 53, 62, 54, 55, 59, 61,  0,  0,  0 },
   /* m */ {  1,  0,  0,  0,  7,  0,  0,  0,  0,  0, 10,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 16 },
   /* n */ {  0,  1,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  5,  8, 10,  0,  0,  0,  0,  0, 17,  0,  0,  0,  0,  0 },
   /* o */ {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  1,  2,  5,  0,  0,  0,  0,  0,  0,  9,  0, 11,  0,  0,  0 },
@@ -69,4 +69,4 @@
   /* z */ {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0 }
 };
 
-static const int command_count = 576;
+static const int command_count = 577;