ui/cocoa.m: Update documentation file and pathname

We want to stop generating the old qemu-doc.html; first we
must update places that refer to it so they instead go to
our top level index.html documentation landing page.
The Cocoa UI has a menu option to bring up the documentation;
make it point to the new top level index.html instead.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20200228153619.9906-31-peter.maydell@linaro.org

ui/cocoa.m

@@ -1174,7 +1174,7 @@ - (void)toggleFullScreen:(id)sender
 - (void) openDocumentation: (NSString *) filename
 {
     /* Where to look for local files */
-    NSString *path_array[] = {@"../share/doc/qemu/", @"../doc/qemu/", @"../"};
+    NSString *path_array[] = {@"../share/doc/qemu/", @"../doc/qemu/", @"../docs/"};
     NSString *full_file_path;
 
     /* iterate thru the possible paths until the file is found */
@@ -1198,7 +1198,7 @@ - (void)showQEMUDoc:(id)sender
 {
     COCOA_DEBUG("QemuCocoaAppController: showQEMUDoc\n");
 
-    [self openDocumentation: @"qemu-doc.html"];
+    [self openDocumentation: @"index.html"];
 }
 
 /* Stretches video to fit host monitor size */