patch 9.0.0375: the footer feature is unused

Problem:    The footer feature is unused.
Solution:   Remove FEAT_FOOTER and code.
diff --git a/src/version.c b/src/version.c
index e3cb074..1ceb171 100644
--- a/src/version.c
+++ b/src/version.c
@@ -254,12 +254,8 @@
 #else
 	"-folding",
 #endif
-#ifdef FEAT_FOOTER
-	"+footer",
-#else
 	"-footer",
-#endif
-	    // only interesting on Unix systems
+	// only interesting on Unix systems
 #if !defined(USE_SYSTEM) && defined(UNIX)
 	"+fork()",
 #endif
@@ -708,6 +704,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    375,
+/**/
     374,
 /**/
     373,