Don't truncate package docs

From googleapis/google-api-go-client#372

https://godoc.org/google.golang.org/api/compute/v0.beta and https://godoc.org/google.golang.org/api/compute/v1 both displays:

The documentation displayed here is incomplete. Use the godoc command to read the complete documentation.

instead of rendering the godoc for the packages.

The current document size limit is 800'000 bytes:

gddo/database/database.go

Lines 263 to 264 in af0f2af

    
           // Truncate large documents. 
        
           if len(gobBytes) > 800000 {

The compute/v0.beta package document size is currently 1'004'901 bytes, and compute/v1 is 834'564 bytes.

Instead of doubling the limit, I am considering going with a more conservative 1.5x multiplier and updating it to 1'200'000 bytes. If we need to exceed that limit further in the future, we can re-evaluate then.

Edit: Sent CL 190398.

/cc @shantuo @stephenmw