fix grammar in strings like "Triggers status"

We have strings in Zabbix frontend that are not entirely correct, like "Triggers status" in "Monitoring" -> "Triggers", which should be replaced with "Trigger status" (also spotted earlier in ZBXNEXT-892).

Here is a list of other strings that have been spotted:

• Triggers status -> Trigger status
• Hosts info -> Host info
• Triggers info -> Trigger info
• Triggers overview -> Trigger overview

The last three appear in screen cell configuration.