Layouts: Optimise the size of some buttons on some layouts

and clean up some layout-files.

Part-of: <https://gitlab.gnome.org/World/Phosh/squeekboard/-/merge_requests/655>

data/keyboards/terminal/us.yaml

@@ -11,7 +11,7 @@ outlines:
     action:        { width: 59,     height: 45.5 }
     wide:          { width: 59,     height: 45.5 }
     change-view-2: { width: 59,     height: 45.5 }
-    spaceline:     { width: 144.96, height: 45.5 }
+    spaceline:     { width: 138.63, height: 45.5 }
     small:         { width: 50.471, height: 24 }
 
 views:
@@ -37,7 +37,7 @@ views:
         - "TabSmall Ctrl Alt ↑ ↓ ← →"
         - "~ ` · √ π τ ÷ × ¶ @"
         - "-- © ® £ € ¥ ^ ° { } --"
-        - "show_numbers  % | < > = [ ]  BackSpace"
+        - "show_numbers_from_symbols  % | < > = [ ]  BackSpace"
         - "show_letters preferences         space        . Return"
     actions:
         - "TabSmall Ctrl Alt PageUp PageDown Home End"
@@ -63,6 +63,11 @@ buttons:
         outline: "special"
         icon: "keyboard-mode-symbolic"
     show_numbers:
+        action:
+            set_view: "numbers"
+        outline: "change-view-2"
+        label: "123"
+    show_numbers_from_symbols:
         action:
             set_view: "numbers"
         outline: "change-view"
@@ -70,7 +75,7 @@ buttons:
     show_letters:
         action:
             set_view: "base"
-        outline: "change-view"
+        outline: "change-view-2"
         label: "ABC"
     show_letters_actions:
         action: