I don’t think you’re going to find a Bolt-specific or even a Gen 2 Volt-specific Infotainment manual.
The Infotainment section of the 2017 Volt Owner’s Manual says simply that your vehicle has an infotainment system. See the infotainment manual. The infotainment manual covers the infotainment center found in several Chevrolet vehicles.
The introduction to the "2017 Chevrolet MyLink Infotainment System" manual states, "the content may apply to the infotainment systems found in the Silverado, Colorado, Tahoe, Suburban, Camaro, Cruze, Malibu, Impala, and Volt vehicles... The information in this manual supplements the owner manual. This manual includes the latest information available at the time it was printed... This manual describes features that may or may not be on the vehicle because of optional equipment that was not purchased on the vehicle, model variants, country specifications, features/applications that may not be available in your region, or changes subsequent to the printing of this manual."
Regarding text messaging, this manual says, "Before using the text messaging feature, check to see if the phone is compatible. To view compatible phones in USA, see my.chevrolet.com." Perhaps that website will mention if there are phones compatible with the Bolt for use in text messaging, which would imply that some or all Bolts may have this feature.
I suspect they will eventually update the manual to include the Bolt.