docs: fix typo in sync_windows.md (argoproj#6334)

Signed-off-by: Vadym Liubko <[email protected]>

docs/user-guide/sync_windows.md

@@ -7,7 +7,7 @@ of both manual and automated syncs but allow an override for manual syncs which
 in preventing automated syncs or if you need to temporarily override a window to perform a sync.
 
 The windows work in the following way. If there are no windows matching an application then all syncs are allowed. If there
-are any `allow` windows matching an application then syncs will only be allowed when there ia an active `allow` windows. If there
+are any `allow` windows matching an application then syncs will only be allowed when there is an active `allow` windows. If there
 are any `deny` windows matching an application then all syncs will be denied when the `deny` windows are active. If there is an
 active matching `allow` and an active matching `deny` then syncs will be denied as `deny` windows override `allow` windows. The
 UI and the CLI will both display the state of the sync windows. The UI has a panel which will display different colours depending
@@ -108,4 +108,4 @@ contains default and kube-system then the new value would have to include those
 
 ```bash
 argocd proj windows update PROJECT ID --namespaces default,kube-system,prod1
-```
+```