Write troubleshooting docs for max alerts warning

[nastasha-solomon]

Description

In 8.8, users will see a warning display on the rule details page if a rule hits the max number of alerts that it can generate. The copy for the warning is still being developed and it's possible that we'll need to write troubleshooting docs to give users a way to resolve the warning message.

Related:

• [Security Solution] Adds max signals warning to UI propagated rule warnings kibana#154112

Notes

• Additional information about what triggers the warning and potential next steps users can take can be found here.
• A separate dev PR will be opened for the UI copy if more changes are needed.

cc: @dplumlee

[nastasha-solomon]

Current copy for message is at: https://github.com/elastic/kibana/pull/154112/files#diff-430791d3baadf1fe0e83355a43da183474c62050771a5f485022f45bb5b00d0dR958

cc: @dplumlee