History - fix off-by-one error

src/vm/commands/redo.ts

@@ -24,7 +24,7 @@ export class Redo extends Command<{ steps?: StrTerm }> {
                 : 1
 
             await vm.control$.next({ cmd: 'preserve-history' })
-            for ( let i = 0; i <= steps; i++) {
+            for ( let i = 0; i < steps; i++) {
                 await vm.control$.next({ cmd: 'redo' })
             }
 

src/vm/commands/undo.ts

@@ -24,7 +24,7 @@ export class Undo extends Command<{ steps?: StrTerm }> {
                 : 1
 
             await vm.control$.next({ cmd: 'preserve-history' })
-            for ( let i = 0; i <= steps; i++) {
+            for ( let i = 0; i < steps; i++) {
                 await vm.control$.next({ cmd: 'undo' })
             }