Add configurable inline-comment whitespace rule and enable for Bash

[notfoundzzz]

Motivation

• Replace a Bash-only hardcoded special-case for recognizing # comments with a configurable parser option to avoid ad-hoc per-language code and make the rule data-driven.
• Allow languages to require whitespace before inline comment starts so constructs like $# or ${#var} are not mis-highlighted as comments in Bash.

Description

• Added a boolean flag and setter to the inline comment parser by updating src/Data/Parser/inline_comment_parser.hpp and src/Data/Parser/inline_comment_parser.cpp (m_require_space_before and set_require_space_before).
• Made the parser obey the whitespace rule by returning false from can_parse() when m_require_space_before is true and the previous character is not whitespace in inline_comment_parser.cpp.
• Wired a new space_before comment feature in prog_language_rep::customize_comment in src/System/Language/prog_language.cpp so languages can enable the rule via parser features and removed the previous Bash-specific # handling in get_color.
• Enabled the rule for Bash by adding (space_before "true") to the Bash language config in TeXmacs/plugins/bash/progs/code/bash-lang.scm under the comment parser feature.

Testing

• No automated tests were executed as part of this change (no test run was requested).

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Codex Task