curl_easy_pause.3: minor wording edit

While it may feel tempting, take care and notice that you cannot call this

function from another thread. To unpause, you may for example call it from the

progress callback (see \fIcurl_easy_setopt(3)\fP's

\fICURLOPT_PROGRESSFUNCTION(3)\fP), which gets called at least once per

second, even if the connection is paused.

progress callback (\fICURLOPT_PROGRESSFUNCTION(3)\fP), which gets called at

least once per second, even if the connection is paused.

When this function is called to unpause reading, the chance is high that you

will get your write callback called before this function returns.