Fixed main/-main error message

gcc/cobol/BLOG.md

gcc/cobol/ChangeLog

gcc/cobol/Make-lang.in

gcc/cobol/UAT/testsuite.src/fixed_format.at

gcc/cobol/UAT/testsuite.src/fundamental.at

gcc/cobol/UAT/testsuite.src/run_functions.at

gcc/cobol/UAT/testsuite.src/run_fundamental.at

gcc/cobol/UAT/testsuite.src/run_misc.at

gcc/cobol/UAT/testsuite.src/run_regression.at

gcc/cobol/UAT/testsuite.src/syn_copy.at

gcc/cobol/UAT/testsuite.src/syn_definition.at

gcc/cobol/UAT/testsuite.src/syn_file.at

gcc/cobol/UAT/testsuite.src/syn_misc.at

gcc/cobol/UAT/testsuite.src/syn_move.at

gcc/cobol/UAT/testsuite.src/syn_redefines.at

gcc/cobol/UAT/testsuite.src/syn_refmod.at

gcc/cobol/UAT/testsuite.src/syn_set.at

gcc/cobol/UAT/testsuite.src/syn_subscripts.at

gcc/cobol/UAT/testsuite.src/syn_value.at

gcc/cobol/cbldiag.h