patch 8.1.0706: tabline is not always redrawn

Problem:    Tabline is not always redrawn when something that is used in
            'tabline' changes.
Solution:   Add ":redrawtabline" so that a plugin can at least cause the
            redraw when needed.
diff --git a/src/ex_cmdidxs.h b/src/ex_cmdidxs.h
index 1c435ca..8b7c85c 100644
--- a/src/ex_cmdidxs.h
+++ b/src/ex_cmdidxs.h
@@ -23,14 +23,14 @@
   /* p */ 309,
   /* q */ 348,
   /* r */ 351,
-  /* s */ 370,
-  /* t */ 437,
-  /* u */ 480,
-  /* v */ 491,
-  /* w */ 509,
-  /* x */ 524,
-  /* y */ 533,
-  /* z */ 534
+  /* s */ 371,
+  /* t */ 438,
+  /* u */ 481,
+  /* v */ 492,
+  /* w */ 510,
+  /* x */ 525,
+  /* y */ 534,
+  /* z */ 535
 };
 
 /*
@@ -58,7 +58,7 @@
   /* 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 },
   /* p */ {  1,  0,  3,  0,  4,  0,  0,  0,  0,  0,  0,  0,  0,  0,  7,  9,  0,  0, 16, 17, 26,  0, 27,  0, 28,  0 },
   /* q */ {  2,  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 },
-  /* r */ {  0,  0,  0,  0,  0,  0,  0,  0, 11,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 13, 18,  0,  0,  0,  0 },
+  /* r */ {  0,  0,  0,  0,  0,  0,  0,  0, 12,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 14, 19,  0,  0,  0,  0 },
   /* s */ {  2,  6, 15,  0, 18, 22,  0, 24, 25,  0,  0, 28, 30, 34, 38, 40,  0, 48,  0, 49,  0, 61, 62,  0, 63,  0 },
   /* t */ {  2,  0, 19,  0, 22, 24,  0, 25,  0, 26,  0, 27, 31, 34, 36, 37,  0, 38, 40,  0, 41,  0,  0,  0,  0,  0 },
   /* u */ {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 10,  0,  0,  0,  0,  0,  0,  0,  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 = 547;
+static const int command_count = 548;