[RUST] Implement escape reserved word for Rust Client codegen.

[scottmmjackson]

The Bitbucket Cloud API has "ref" as a swagger symbol. Thus on master it fails with a reserved word error. After this change, this should work:

$ ./run-in-docker.sh generate -i https://dac-static.atlassian.com/cloud/bitbucket/swagger.v3.json?_v=2.300.22-0.1297.0 -g rust -o /gen/out/

@frol @farcaller @richardwhiuk @paladinzh @jacob-pro

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[scottmmjackson]

#17795 and #17368 are likely fixed by this change

[jacob-pro]

I thought the Rust generator already implemented this - or am I missing something? This will need some test cases to demonstrate either way

https://github.com/OpenAPITools/openapi-generator/blob/ec42f88c6a27a0d422390ecdf5adb5785b2be5e7/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractRustCodegen.java#L215-L223

[scottmmjackson]

@jacob-pro I can definitely add some tests. #17795 is the issue this comes from, where escaping reserved words is not working.

This is probably because the abstract code you cited isn't the right place to escape. The DefaultCodegen implements it as a pure throw:

https://github.com/OpenAPITools/openapi-generator/blob/ec42f88c6a27a0d422390ecdf5adb5785b2be5e7/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java#L1760

This is why when attempting to use this generator, we get this in the stack trace:

Caused by: java.lang.RuntimeException: reserved word ref not allowed
	at org.openapitools.codegen.DefaultCodegen.escapeReservedWord(DefaultCodegen.java:1752)

BTW, based on your highlighting AbstractRustCodegen, I almost wonder if overriding the method in AbstractRustCodegen by moving the block you highlighted out into a separate member is the right choice here... thoughts?

[scottmmjackson]

Been playing around with moving this to an override and it's proving kinda difficult. It seems like we have a variety of context-specific prefixes we're using, and escapeReservedWord doesn't know about context. I think this will end up having to change output, unless someone has a better idea.

[wing328]

merged via https://github.com/OpenAPITools/openapi-generator/pull/17440 instead

thanks for the PR