Improves documentation for `Select Frame` and `Unselect Frame`. (#919)
Improves documentation for `Select Frame` and `Unselect Frame`. (#919)

* Improves documentation for `Select Frame` and `Unselect Frame`.
For #892.

Added note on having to Unselect Frame to start searching from main frame.

Expanded examples.

rtomac/robotframework-selenium2library,rtomac/robotframework-selenium2library,emanlove/robotframework-selenium2library,rtomac/robotframework-selenium2library,emanlove/robotframework-selenium2library,emanlove/robotframework-selenium2library,robotframework/SeleniumLibrary,robotframework/SeleniumLibrary,robotframework/SeleniumLibrary