docs: Fix grammar mistakes and typos.

Created by: serenashe

Signed-off-by: serenashe serenashe@kubesphere.io

What type of PR is this?

/kind documentation

What this PR does / why we need it:

Fix grammar mistakes and typos on the web console.

Special notes for reviewers:

None

Does this PR introduced a user-facing change?

None

/assign @Patrick-LuoYu @harrisonliu5 Please take a look at this PR, thanks :)