Rust: Improve/add various models

[hvitved]

Based on triaging some MISSING tags:

• Fixes some Argument[Self] -> Argument[self] typos.
• Removes the incorrect manual models for as_mut_os_string and into_os_string; the generated models are accurate.
• Adds various other models.

DCA is fine.

[Copilot]

Pull request overview

This PR improves Rust dataflow models by fixing typos and adding missing models based on triaging MISSING tags in test expectations.

Changes:

• Fixes Argument[Self] → Argument[self] typos in fs.model.yml
• Removes incorrect manual models for as_mut_os_string and into_os_string (relying on generated models instead)
• Adds new models for HTTP response body accessors, stdin read_line, Path/OsStr methods, Vec/slice deref, and borrow::Cow::to_mut

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
rust/ql/lib/codeql/rust/frameworks/stdlib/io.model.yml	Adds stdin read_line taint model
rust/ql/lib/codeql/rust/frameworks/stdlib/fs.model.yml	Fixes Self→self typos, removes incorrect manual models, adds missing Path methods
rust/ql/lib/codeql/rust/frameworks/stdlib/ffi.model.yml	Adds OsStr to_str, to_string_lossy, as_encoded_bytes models
rust/ql/lib/codeql/rust/frameworks/stdlib/core.model.yml	Adds slice get model
rust/ql/lib/codeql/rust/frameworks/stdlib/alloc.model.yml	Adds Vec deref model, Cow::to_mut model
rust/ql/lib/codeql/rust/frameworks/http.model.yml	Adds Response body accessors
rust/ql/test/query-tests/security/CWE-295/*	Updates test expectations (auto-generated)
rust/ql/test/query-tests/security/CWE-117/*	Updates test expectations (auto-generated)
rust/ql/test/library-tests/dataflow/sources/net/*	Updates test expectations (auto-generated)
rust/ql/test/library-tests/dataflow/sources/file/*	Updates test expectations (auto-generated)

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[geoffw0]

Looks great, thank you for your diligence!