Default config in v3.4 is different from code

[divanodestiny]

website vs doc

[jmhbnz]

Reviewing this old issue while doing triage I can confirm this is still an issue, thanks for reporting it @divanodestiny and sorry this did not get reviewed sooner, the etcd project has not had enough contributors to respond to all issues.

The current documentation for v3.4 states:

### --backend-bbolt-freelist-type
+ The freelist type that etcd backend(bboltdb) uses (array and map are supported types).
+ default: map
+ env variable: ETCD_BACKEND_BBOLT_FREELIST_TYPE

The code on release-3.4 stable branch states:

  --experimental-backend-bbolt-freelist-type 'array'
    ExperimentalBackendFreelistType specifies the type of freelist that boltdb backend uses(array and map are supported types).

etcd-io/etcd#11262 promoted the feature from experimental for release-3.5 only but somehow the documentation update changing the flag from experimental also got applied to the 3.4 docs.

This would be a quick fix to just update the flag in the v3.4 op guide to --experimental-backend-bbolt-freelist-type and update the default to array so the docs match the v3.4 code.

[ahrtr]

Resolved in #778