docs: changelog for https://github.com/wez/wezterm/issues/1615

docs/changelog.md

@@ -25,6 +25,7 @@ As features stabilize some brief notes about them will accumulate here.
 * Workspaces. Follow work in progress on [#1531](https://github.com/wez/wezterm/issues/1531) and [#1322](https://github.com/wez/wezterm/discussions/1322)! [window:active_workspace()](config/lua/window/active_workspace.md), [default_workspace](config/lua/config/default_workspace.md), [SwitchWorkspaceRelative](config/lua/keyassignment/SwitchWorkspaceRelative.md), [SwitchToWorkspace](config/lua/keyassignment/SwitchToWorkspace.md)
 * `wezterm cli send-text "hello"` allows sending text, as though pasted, to a pane. See `wezterm cli send-text --help` for more information. [#888](https://github.com/wez/wezterm/issues/888)
 * `local_echo_threshold_ms` option to adjust the predictive local echo timing for [SshDomain](config/lua/SshDomain.md), [TlsDomainClient](config/lua/TlsDomainClient.md) and [unix domains](multiplexing.md). Thanks to [@qperret](https://github.com/qperret)! [#1518](https://github.com/wez/wezterm/pull/1518)
+* It is now possible to set `selection_fg` and `selection_bg` to be fully or partially transparent. [Read more](config/appearance.md). [#1615](https://github.com/wez/wezterm/issues/1615)
 
 #### Changed
 

docs/config/appearance.md

@@ -88,6 +88,30 @@ return {
 }
 ```
 
+*Since: nightly builds only*
+
+`selection_fg` and `selection_bg` may set the alpha channel value.
+
+```lua
+return {
+  colors = {
+    -- Make the selection text color fully transparent.
+    -- When fully transparent, the current text color will be used.
+    selection_fg = "none",
+    -- Set the selection background color with alpha;
+    -- The first number is the red channel, set here to 50%.
+    -- If the number doesn't end with a % then it must be in the range
+    -- 0 through 255.
+    -- The second number is the green channel.
+    -- The third number is the blue channel.
+    -- The last number is the alpha channel.
+    -- When selection_bg is transparent, it will be alpha blended over
+    -- the current cell background color, rather than replace it
+    selection_bg = "rgba:50% 50% 50% 50%"
+  }
+}
+```
+
 ### Defining a Color Scheme in your `.wezterm.lua`
 
 If you'd like to keep a couple of color schemes handy in your configuration