[patch] Change trace buffer size(v5)

[Joel Brobecker]

> +@item QTBuffer:size
> +The remote stub supports the @samp{QTBuffer:size} (@pxref{QTBuffer:size})
> +packet that allows to change the size of the trace buffer.

This causes the documenation to fail, which also affect the nightly
packaging of the sources:

./gdb.texinfo:37555: Cross reference to nonexistent node `QTBuffer:size' (perhaps incorrect sectioning?).

I am about to fly back home, can you fix this error?

Thank you,
-- 
Joel