patch 9.2.0055: memory leak in ExpandFromContext()

Problem:  memory leak in ExpandFromContext()
Solution: Free the variable (Huihui Huang).

fixes:  #19500
closes: #19505

Co-authored-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Huihui Huang <625173@qq.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/cmdexpand.c

@@ -3515,8 +3515,10 @@ ExpandFromContext(
     {
 	regmatch.regprog = vim_regcomp(pat, magic_isset() ? RE_MAGIC : 0);
 	if (regmatch.regprog == NULL)
+	{
+	    vim_free(tofree);
 	    return FAIL;
-
+	}
 	// set ignore-case according to p_ic, p_scs and pat
 	regmatch.rm_ic = ignorecase(pat);
     }

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    55,
 /**/
     54,
 /**/