process is running or @code{t} if the process is stopped.
@item filter
-If non-@code{nil}, a function used to accept output from the process
-instead of a buffer.
+A function used to accept output from the process.
@item sentinel
-If non-@code{nil}, a function called whenever the state of the process
-changes.
+A function called whenever the state of the process changes.
@item buffer
The associated buffer of the process.