Allow terminal symbols to be used anywhere in the grammar rules

[ydah]

Fixes: #182

[Copilot]

Pull Request Overview

This PR fixes issue #182 by allowing terminal symbols to be used anywhere within grammar rules, not just at specific positions. The change enables more flexible grammar rule definitions where terminal symbols can appear in any part of a production rule.

• Adds support for terminal symbols in any position within grammar rules
• Introduces proper handling of rule continuation with OrMark symbols
• Maintains current rule target state across rule definitions

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
lib/racc/grammarfileparser.rb	Core logic changes to track current rule target and handle rule continuations with OrMark
test/assets/term.y	Test grammar file demonstrating terminal symbols used in various positions
test/regress/term	Generated parser output from the test grammar
test/test_racc_command.rb	New test case to verify the terminal symbol functionality

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