cli: add +show-face CLI action

This CLI action shows what font face Ghostty will use to display
a particular codepoint.

src/cli/action.zig

@@ -12,6 +12,7 @@ const list_actions = @import("list_actions.zig");
 const show_config = @import("show_config.zig");
 const validate_config = @import("validate_config.zig");
 const crash_report = @import("crash_report.zig");
+const show_face = @import("show_face.zig");
 
 /// Special commands that can be invoked via CLI flags. These are all
 /// invoked by using `+<action>` as a CLI flag. The only exception is
@@ -47,6 +48,9 @@ pub const Action = enum {
     // List, (eventually) view, and (eventually) send crash reports.
     @"crash-report",
 
+    // Show which font face Ghostty loads a codepoint from.
+    @"show-face",
+
     pub const Error = error{
         /// Multiple actions were detected. You can specify at most one
         /// action on the CLI otherwise the behavior desired is ambiguous.
@@ -146,6 +150,7 @@ pub const Action = enum {
             .@"show-config" => try show_config.run(alloc),
             .@"validate-config" => try validate_config.run(alloc),
             .@"crash-report" => try crash_report.run(alloc),
+            .@"show-face" => try show_face.run(alloc),
         };
     }
 
@@ -180,6 +185,7 @@ pub const Action = enum {
                 .@"show-config" => show_config.Options,
                 .@"validate-config" => validate_config.Options,
                 .@"crash-report" => crash_report.Options,
+                .@"show-face" => show_face.Options,
             };
         }
     }