Match filename in xvlog linter and add tip

[gastmaier]

Match the xvlog stdout for the filename to properly filter out the errors per file. Suggest using Vivado generated compile.sh file to obtain the xvlog options.

For reference, the sane way of using xvlog is along these lines:

let g:ale_verilog_xvlog_options = '
\ --incr --relax \
\ -L uvm -L axi_vip_v1_1_15 -L smartconnect_v1_0 -L clk_vip_v1_0_3 -L axi4stream_vip_v1_1_15 -L rst_vip_v1_0_5 -L xilinx_vip
\ -prj ./path/to/xsim/system_tb_vlog.prj'

Room for improvement: The .prj uses relative paths and expects xvlog to be called from its path. As is, I'm manually "fixing" the relative paths in the .prj to point from the cwd to xsim. Not sure if it's worth a more elaborated solution (e.g. search for the compile.sh, set cwd to its location, and extract the xvlog options.