qw(@con) is an error. Perl would have told you about it if you used strictures (use strict; use warnings;). Always use strictures. qw quotes 'words' where in this case a 'word' is any sequence of non-white space characters. @con is taken to be a word by qw so you are trying to assign a single element list to a hash - that doesn't do what you want.

Consider instead:

use strict;
use warnings;

my %con;

while (<DATA>) {
    chomp($_);
    next unless /^(.*?)=>(.*)/;
    
    $con{$1} = $2;
}

print "Key: $_, Value: $con{$_}\n" for sort keys %con;

__DATA__
article=>art
chapter=>chap
section=>sec
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Prints:

Key: article, Value: art
Key: chapter, Value: chap
Key: section, Value: sec
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