doc: Remove repetitive "Give grep a chance" phrase from comments

* Follows-up b2e2b2e016.
* Minor clean up of surrounding documentation comments.
* Fixed missing keys for messages in WebInstallerPage

Change-Id: Iaa692064262f3c0e10cfa5e4b1ec8c86e5d02362
Merge "doc: Remove repetitive "Give grep a chance" phrase from comments"