patch 8.2.2811: Vim9: error for missing white space doesn't say where

Problem:    Vim9: error for missing white space doesn't say where it is
            missing
Solution:   Mention the command. (closes #8149)

src/errors.h

@@ -323,8 +323,8 @@ EXTERN char e_non_empty_string_required[]
 	INIT(= N_("E1142: Non-empty string required"));
 EXTERN char e_empty_expression_str[]
 	INIT(= N_("E1143: Empty expression: \"%s\""));
-EXTERN char e_command_not_followed_by_white_space_str[]
-	INIT(= N_("E1144: Command is not followed by white space: %s"));
+EXTERN char e_command_str_not_followed_by_white_space_str[]
+	INIT(= N_("E1144: Command \"%s\" is not followed by white space: %s"));
 EXTERN char e_missing_heredoc_end_marker_str[]
 	INIT(= N_("E1145: Missing heredoc end marker: %s"));
 EXTERN char e_command_not_recognized_str[]

src/ex_docmd.c

@@ -3673,8 +3673,11 @@ find_ex_command(
 	    && (eap->cmdidx < 0 ||
 		(cmdnames[eap->cmdidx].cmd_argt & EX_NONWHITE_OK) == 0))
     {
-	semsg(_(e_command_not_followed_by_white_space_str), eap->cmd);
+	char_u *cmd = vim_strnsave(eap->cmd, p - eap->cmd);
+
+	semsg(_(e_command_str_not_followed_by_white_space_str), cmd, eap->cmd);
 	eap->cmdidx = CMD_SIZE;
+	vim_free(cmd);
     }
 #endif
 

src/testdir/test_vim9_cmd.vim

@@ -994,8 +994,16 @@ def Test_user_command_comment()
       Comd# comment
   END
   CheckScriptFailure(lines, 'E1144:')
-
   delcommand Comd
+
+  lines =<< trim END
+      vim9script
+      command Foo echo 'Foo'
+      Foo3Bar
+  END
+  CheckScriptFailure(lines, 'E1144: Command "Foo" is not followed by white space: Foo3Bar')
+
+  delcommand Foo
 enddef
 
 def Test_star_command()

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2811,
 /**/
     2810,
 /**/