Update 4.5 release notes with OSD HD default and others

[ctzsnooze]

Some quick notes about the default behaviour when OSD_HD is included in the build (clean flash will configure the board for OSD_HD, not for Analog, by default).

A few other tidy-ups.

Anything else we should mention / do?

[sonarcloud[bot]]

Quality Gate passed

Kudos, no new issues were introduced!

0 New issues
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud