[OOB 5.10] Missing configuration item in API reference doc

[coisme]

In the API reference, an configuration item nvstore.enabled is missing.

My output from mbed compile --config -v:

Name: nvstore.area_1_address
    Description: Area 1 address
    Defined by: library:nvstore
    No value set
Name: nvstore.area_1_size
    Description: Area 1 size
    Defined by: library:nvstore
    No value set
Name: nvstore.area_2_address
    Description: Area 2 address
    Defined by: library:nvstore
    No value set
Name: nvstore.area_2_size
    Description: Area 2 size
    Defined by: library:nvstore
    No value set
Name: nvstore.enabled
    Description: Enabled
    Defined by: library:nvstore
    Macro name: NVSTORE_ENABLED
    Value: 1 (set by library:nvstore)
Name: nvstore.max_keys
    Description: Maximal number of allowed NVStore keys
    Defined by: library:nvstore
    Macro name: NVSTORE_MAX_KEYS
    Value: 16 (set by library:nvstore)

[ciarmcom]

ARM Internal Ref: MBOTRIAGE-1602

[ashok-rao]

@geky .. can you please check this? Thanks.

[kegilbert]

Good catch! Have a PR up at:

ARMmbed/mbed-os-5-docs#724

[AnotherButler]

@coisme I'm closing this because I've merged the fix PR from @kegilbert
Please feel free to reopen if this PR does not satisfy your requirements