application-framework: Change quoting to italics for clarity

This is simply specifying what a runtime is, so the use of quotes is a
bit confusing.

https://phabricator.apertis.org/T8426



Signed-off-by: Ryan Gonzalez <ryan.gonzalez@collabora.com>

content/concepts/application-framework.md

@@ -183,7 +183,7 @@ and less network bandwidth.
 Flatpak decouples applications from the underlying Operating System,
 so that they can follow different release schedules minimizing the impact of
 conflicting changes: applications in Flatpak rely on basic set of libraries
-called "runtimes" that shield them from the actual libraries used by the OS.
+called *runtimes* that shield them from the actual libraries used by the OS.
 OSTree helps to keep this redundancy under control, minimizing the storage
 consumption by de-duplicating items in common.
 Runtimes help to keep the base OS lean and minimal as non-core libraries