3bbdbc0a5e qt, docs: Unify term "clipboard" (Hennadii Stepanov)
Pull request description:
A translator on Transifex noticed:
> The term "system clipboard" appears twice. The term "clipboard" appears 10 times. Perhaps we could standardize on just saying "clipboard"?
This PR addresses this issue.
ACKs for top commit:
davidgumberg:
ACK 3bbdbc0a5e
pablomartin4btc:
ACK 3bbdbc0a5e
Tree-SHA512: 61a100f60890d81122a4b8ce3e2cb7d355c7fb643de3196573f7f9107c6f52fa0b3e7a4f743ce2833e8c67b9cdad3568b761d730fef5c9781f5e1c45252888c4