flatpak: add instructions for building with QSV support

source/docs/en/latest/developer/flatpak-repo.markdown

@@ -18,6 +18,7 @@ Creating HandBrake flatpak bundles and repository
 =================================================
 
 ## Install dependencies
+
 Install flatpak and flatpak-builder
 
     sudo dnf install flatpak flatpak-builder
@@ -35,12 +36,15 @@ Install flatpak freedesktop runtime platform.
     flatpak install flathub org.freedesktop.Platform//18.08
 
 ## Create a new HandBrake flatpak bundle
-This may be done on a different machine than the repo.
 
 From the HandBrake source tree, update build versions by running configure
 
     ./configure --flatpak
 
+Or to build HandBrake with Quick Sync Video support and HandBrake's Intel MediaSDK flatpak plugin
+
+    ./configure --flatpak --enable-qsv
+
 Build signed flatpak packages for GUI and CLI.
 
     cd build
@@ -62,11 +66,13 @@ And an OSTree repository where the packages have been committed and signed with
 If PGP_ID is omitted, the OSTree commit will be unsigned.
 
 ## Install flatpak bundle
+
 To use the flatpak bundle directly instead of importing it into a repository and then installing from the repository:
 
     flatpak install <flatpak-bundle>
 
 ## Add OSTree repo to flatpak repo list (Optional)
+
 This is only for test purposes currently.  Ultimately, we might want to establish an "official" repo location that we publish new bundles to.  Currently, the repo is just a product of the build and is not meant to be reused across builds.
 
 Add the new repository to your flatpak remotes
@@ -78,6 +84,7 @@ Of if the repos was generated without PGP signed commits
     flatpak --user remote-add --no-gpg-verify <repo-name> <repo-dir>
 
 ## Check repo and application (Optional)
+
 List contents of the repo
 
     flatpak --user remote-ls <repo-name>
@@ -87,6 +94,7 @@ Install the application (if you wish to test it)
     flatpak --user install <repo-name> <app-name>
 
 # Maintaining a separate OSTree repository
+
 There are situations where you don't want to keep your repository on the same server as you built the flatpak on.  Rather than exporting the entire repo-dir that is built by flatpak-builder, you can import your bundles into a seperate OSTree repository.
 
 ## Create a new empty repository
@@ -96,6 +104,7 @@ ostree init --mode=archive-z2 --reop=<repo-dir>
 ```
 
 ## Add flatpakrepo file to the repository
+
 This file is used by flatpak clients to add your repoitory to their list of remotes.
 
 Create a file named \<yourproject\>.flatpakrepo in \<repo-dir\>.  The format looks like this:
@@ -133,6 +142,7 @@ flatpak build-update-repo --generate-static-deltas --gpg-sign=<key-id>
 ```
 
 ## Host your repository with a web server
+
 For test purposes, I just use pythons builtin web server.
 
 ```
@@ -142,6 +152,7 @@ python3 -m http.server 8080 --directory <repo-dir>
 Note, requires python 3.7 or above.
 
 ## Publish the location of \<yourproject\>.flatpakrepo
+
 Users can add your repository to their list of remotes with:
 
 ```