Merge #180: Peer details: connection type follow-ups

79a2576af1 doc: update ConnectionType Doxygen documentation (Jon Atack)
f3153dc08f gui: improve markup handling of connection type tooltip (Jon Atack)
4f09615733 gui: return inbound {full, block} relay type in peer details (Jon Atack)

Pull request description:

  Three follow-ups to #163:
  - return relay type for inbound peers
  - improve markup handling in the tooltip to facilitate translations
  - update ConnectionType doxygen documentation

  ![Screenshot from 2021-01-11 08-37-44](https://user-images.githubusercontent.com/2415484/104156081-50e69300-53e0-11eb-9b0f-880cb5626d68.png)

ACKs for top commit:
  hebasto:
    re-ACK 79a2576af1, only suggested changes since my [previous](https://github.com/bitcoin-core/gui/pull/180#pullrequestreview-564894781) review.
  jarolrod:
    ACK 79a2576af1, tested on macOS 11.1 with Qt 5.15.2
  laanwj:
    Code review ACK 79a2576af1

Tree-SHA512: 4a8d8f8bfbaefd68e8d1bf3b20d29e4a8e8cfe97b2f8d59d3a4c338a50b61de0a67d97bd8646c04bd5df5a9679c4954b9b46e7cba24bb89f4d0e44e94cf9d66c

src/qt/forms/debugwindow.ui

@@ -1079,7 +1079,7 @@
                <item row="1" column="0">
                 <widget class="QLabel" name="peerConnectionTypeLabel">
                  <property name="toolTip">
-                   <string>The type of peer connection:&lt;ul&gt;&lt;li&gt;Inbound: initiated by peer&lt;/li&gt;&lt;li&gt;Outbound Full Relay: default&lt;/li&gt;&lt;li&gt;Outbound Block Relay: does not relay transactions or addresses&lt;/li&gt;&lt;li&gt;Outbound Manual: added using RPC %1 or %2/%3 configuration options&lt;/li&gt;&lt;li&gt;Outbound Feeler: short-lived, for testing addresses&lt;/li&gt;&lt;li&gt;Outbound Address Fetch: short-lived, for soliciting addresses&lt;/li&gt;&lt;/ul&gt;</string>
+                   <string>The type of peer connection: %1</string>
                  </property>
                  <property name="text">
                   <string>Connection Type</string>