patch 8.2.1429: Vim9: no error for missing white after : in dict

Problem:    Vim9: no error for missing white after : in dict.
Solution:   Check for white space. (closes #6671)  Also check that there is no
            white before the :.
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index 3d16053..a942dd4 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -1494,6 +1494,10 @@
   mixed = #{a: 234}
   mixed = #{}
 
+  call CheckDefFailure(["let x = #{a:8}"], 'E1069:')
+  call CheckDefFailure(["let x = #{a : 8}"], 'E1068:')
+  call CheckDefFailure(["let x = #{a :8}"], 'E1068:')
+
   call CheckDefFailure(["let x = #{8: 8}"], 'E1014:')
   call CheckDefFailure(["let x = #{xxx}"], 'E720:')
   call CheckDefFailure(["let x = #{xxx: 1", "let y = 2"], 'E722:')
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 24078f5..1f9768f 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -774,7 +774,7 @@
     enddef
 
     def RetListAny(): list<any>
-      return items({'k' : 'v'})
+      return items({'k': 'v'})
     enddef
 
     def RetListString(): list<string>
diff --git a/src/version.c b/src/version.c
index 46d027d..b290fdc 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1429,
+/**/
     1428,
 /**/
     1427,
diff --git a/src/vim9compile.c b/src/vim9compile.c
index dfcff50..502c66f 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -2593,14 +2593,21 @@
 	    }
 	}
 
-	*arg = skipwhite(*arg);
 	if (**arg != ':')
 	{
-	    semsg(_(e_missing_dict_colon), *arg);
+	    if (*skipwhite(*arg) == ':')
+		semsg(_(e_no_white_before), ":");
+	    else
+		semsg(_(e_missing_dict_colon), *arg);
+	    return FAIL;
+	}
+	whitep = *arg + 1;
+	if (!IS_WHITE_OR_NUL(*whitep))
+	{
+	    semsg(_(e_white_after), ":");
 	    return FAIL;
 	}
 
-	whitep = *arg + 1;
 	*arg = skipwhite(*arg + 1);
 	if (may_get_next_line(whitep, arg, cctx) == FAIL)
 	{