patch 8.2.2292: Vim: expr test fails

Problem:    Vim: expr test fails.
Solution:   Add missing part of "null" support.

Author: brammool

src/eval.c

@@ -3413,12 +3413,19 @@ eval7(
 		    ret = OK;
 		}
 		else if (len == 5 && in_vim9script()
-						&& STRNCMP(s, "false", 4) == 0)
+						&& STRNCMP(s, "false", 5) == 0)
 		{
 		    rettv->v_type = VAR_BOOL;
 		    rettv->vval.v_number = VVAL_FALSE;
 		    ret = OK;
 		}
+		else if (len == 4 && in_vim9script()
+						&& STRNCMP(s, "null", 4) == 0)
+		{
+		    rettv->v_type = VAR_SPECIAL;
+		    rettv->vval.v_number = VVAL_NULL;
+		    ret = OK;
+		}
 		else
 		    ret = eval_variable(s, len, rettv, NULL, TRUE, FALSE);
 	    }

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2292,
 /**/
     2291,
 /**/