style: align comments with the project conventions

Apply a codebase-wide comment audit against the comment conventions:
split banned semicolons and multi-sentence lines into one sentence per
line, cut cross-file and history narration, trim file-top headers to a
single purpose line, and drop verbosity that did not earn its place.
Prose docs (CLAUDE.md, install.md) get the same one-sentence-per-line
and no-semicolon treatment.

modules/tmux/extra.conf

@@ -6,8 +6,8 @@ bind -T copy-mode-vi v send -X begin-selection
 bind -T copy-mode-vi y send -X copy-selection-and-cancel
 bind -T copy-mode-vi MouseDragEnd1Pane send -X copy-selection-and-cancel
 
-# \ splits the pane side-by-side, - splits it stacked; both open the new pane
-# in the current pane's directory, as does c for a new window.
+# \ splits the pane side-by-side, - splits it stacked.
+# Both open the new pane in the current pane's directory, as does c for a new window.
 unbind %
 unbind '"'
 bind \\ split-window -h -c "#{pane_current_path}"
@@ -27,13 +27,14 @@ bind r source-file ~/.config/tmux/tmux.conf \; display-message "tmux.conf reload
 set -ag terminal-overrides ",*:RGB"
 
 # monitor-bell flags a background window in the status bar when it rings the
-# terminal bell while unfocused. bell-action=none suppresses the actual BEL
-# (no beep or flash); the per-window status highlight is independent of it.
+# terminal bell while unfocused.
+# bell-action=none suppresses the actual BEL (no beep or flash).
+# The per-window status highlight is independent of it.
 setw -g monitor-bell on
 set -g bell-action none
 
 # Minimal status bar: session name plus window list only.
-# Colours are left to Stylix, which themes the status and pane styles.
+# Colours are left to Stylix.
 set -g status-position bottom
 set -g status-left " #S "
 set -g status-left-length 20

modules/tmux/tmux.nix

@@ -3,8 +3,8 @@
   lib,
   ...
 }:
-# tmux for the primary user, configured through home-manager. Settings without a
-# home-manager option are read from ./extra.conf.
+# tmux for the primary user, configured through home-manager.
+# Settings without a home-manager option are read from ./extra.conf.
 let
   cfg = config.modules.tmux;
   user = config.user.name;