Automatic merge from submit-queue
fix kubectl create configmap help messages
Signed-off-by: bruceauyeung <ouyang.qinhua@zte.com.cn>
**What this PR does / why we need it**:
1. the first example command actually doesn't specify any keys. i think `with keys for each file` is incorrect.
2. `names on disk` is confusing. in usage the word `NAME` means configmap, so i think it's better saying `file basenames on disk`
3. in this context, `--from-file` can be specified multiple times, but in each occurance only one key file can be specified, besides we should keep consistent with the later case (key is specified). so i changed words in this sentence to singular. and to avoid confusing, i use `key` instead of `name`