Adding a pretty debug implementation to overcome escaping of strings

[edmondop]

As described in #518 , parsing a string and include it in code generation generates code like so:

            pub mod repository_with_pull_requests {
                #![allow(dead_code)]
                use std::result::Result;
                pub const OPERATION_NAME: &str = "RepositoryWithPullRequests";
                pub const QUERY: &str = "query RepositoryWithPullRequests(\n  $repositoryName: String!\n  $repositoryOwner: String!\n  $count: Int!\n  $pullRequestStates: [PullRequestState!]!\n) {\n  repository(name: $repositoryName, owner: $repositoryOwner) {\n    owner {\n      __typename\n      login\n    }\n    name\n    defaultBranchRef {\n      name\n    }\n    pullRequests(first: $count, states: $pullRequestStates) {\n      pageInfo {\n        hasNextPage\n        endCursor\n      }\n\n      totalCount\n      nodes {\n        author {\n          __typename\n          login\n        }\n        id\n        url\n        title\n        state\n        createdAt\n        updatedAt\n        closedAt\n        ## uh-oh not very safe but it's ok\n        labels(first: 100) {\n          edges {\n            node {\n              id\n              name\n            }\n          }\n        }\n      }\n    }\n  }\n}\n";
                const __QUERY_WORKAROUND: &str = "query RepositoryWithPullRequests(\n  $repositoryName: String!\n  $repositoryOwner: String!\n  $count: Int!\n  $pullRequestStates: [PullRequestState!]!\n) {\n  repository(name: $repositoryName, owner: $repositoryOwner) {\n    owner {\n      __typename\n      login\n    }\n    name\n    defaultBranchRef {\n      name\n    }\n    pullRequests(first: $count, states: $pullRequestStates) {\n      pageInfo {\n        hasNextPage\n        endCursor\n      }\n\n      totalCount\n      nodes {\n        author {\n          __typename\n          login\n        }\n        id\n        url\n        title\n        state\n        createdAt\n        updatedAt\n        closedAt\n        ## uh-oh not very safe but it\'s ok\n        labels(first: 100) {\n          edges {\n            node {\n              id\n              name\n            }\n          }\n        }\n      }\n    }\n  }\n}\n";

instead of a multi-line string. A solution would be to reduce reusability in macros:

pub fn generate_module_token_stream(
    query_path: std::path::PathBuf,
    schema_path: &std::path::Path,
    options: GraphQLClientCodegenOptions,
) -> Result<TokenStream, BoxError> {
    let query = get_set_query_from_file(query_path.as_path());
    let schema = get_set_schema_from_file(schema_path);

    generate_module_token_stream_inner(&query, &schema, options)
}

/// Generates Rust code given a query string, a path to a schema file, and options.
pub fn generate_module_token_stream_from_string(
    query_string: &str,
    schema_path: &std::path::Path,
    options: GraphQLClientCodegenOptions,
) -> Result<TokenStream, BoxError> {
    let query = (query_string.to_string(), query_document(query_string)?);
    let schema = get_set_schema_from_file(schema_path);

    generate_module_token_stream_inner(&query, &schema, options)
}

so that we propagate the path of the file and we use include_str! macro in code-generation if we have something from file, which would require us to modify

/// This struct contains the parameters necessary to generate code for a given operation.
pub(crate) struct GeneratedModule<'a> {
    pub operation: &'a str,
    pub query_string: &'a str,
    pub resolved_query: &'a crate::query::Query,
    pub schema: &'a crate::schema::Schema,
    pub options: &'a crate::GraphQLClientCodegenOptions,
}

to support a query that's either a String or a PathBuf and then at macro time doing either an include or a simple quoting