patch 9.1.0749: filetype: http files not recognized

Problem:  filetype: http files not recognized
Solution: detect '*.http' as http filetype, include
          http filetype plugin (Riley Bruins)

Based on the specification found
[here](https://github.com/JetBrains/http-request-in-editor-spec/blob/master/spec.md)

closes: #15762

Signed-off-by: Riley Bruins <ribru17@hotmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    749,
 /**/
     748,
 /**/