message style for errcontext

We have in 9.0 plperl.c

errcontext("while executing PostgreSQL::InServer::SPI::bootstrap")));
errcontext("while parsing Perl initialization")));
errcontext("while running Perl initialization")));
errcontext("While executing PLC_TRUSTED.")));
errcontext("While executing utf8fix.")));
errcontext("While executing plperl.on_plperl_init.")));
errcontext("while executing plperl.on_plperlu_init")));

Could we agree on a capitalization and punctuation scheme?