docs: correct the untranslated string count

Measured across the whole UI rather than estimated from the settings window:
around 270 visible literals without a resource key, not the hundred the changelog
claimed. The settings window is the bulk of it, but the first-run wizard, the
input bar and the about tab carry their share.

Smoke test for the cycle came back green -- everything works and does what it
says. The untranslated strings are the only known issue.

docs/CHANGELOG.md

@@ -67,9 +67,9 @@ turning up. **Not published** — the public release stays at v1.5.6.
 
 ### Known issues
 
-- Roughly a hundred strings in the settings window are still English on non-English clients: the
-  section headings, the keybind labels, and the descriptions written during this cycle. They have
-  no resource key yet. Translation is planned as its own pass before the tester beta; new strings
+- Around 270 visible strings across the plugin are still English on non-English clients, most of
+  them in the settings window: section headings, keybind labels, and the descriptions written
+  during this cycle. They have no resource key yet. Translation is planned as its own pass before the tester beta; new strings
   ship translated from here on.
 - The first-run wizard, the input bar buttons and the message list itself are still stock ImGui.