Support deprecated API endpoints in reqwest-based Rust clients

Previously, if an API endpoint was marked deprecated, this fact was not
reflected in the generated Rust clients using the reqwest library. We
want to know exactly when our client code is using a deprecated endpoint,
so marking the corresponding functions with the `#[deprecatd]` attribute
would be very helpful. Uses of the endpoint would then be picked up by
linters so that we can react.

This adds a line to the template which marks functions generated from
deprecated endpoints with the `#[deprecated]` attribute.

This does not touch any of the other client generators for Rust or any
other language, since they are out of scope for our needs.

Author: Bradford Hovinen

modules/openapi-generator/src/main/resources/rust/reqwest/api.mustache

@@ -99,6 +99,9 @@ pub enum {{{operationIdCamelCase}}}Error {
 {{#notes}}
 /// {{{.}}}
 {{/notes}}
+{{#isDeprecated}}
+#[deprecated]
+{{/isDeprecated}}
 {{#vendorExtensions.x-group-parameters}}
 pub {{#supportAsync}}async {{/supportAsync}}fn {{{operationId}}}(configuration: &configuration::Configuration{{#allParams}}{{#-first}}, {{!
 ### Params

samples/client/petstore/rust/reqwest/petstore-async-middleware/src/apis/pet_api.rs

@@ -359,6 +359,7 @@ pub async fn find_pets_by_status(configuration: &configuration::Configuration, p
 }
 
 /// Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
+#[deprecated]
 pub async fn find_pets_by_tags(configuration: &configuration::Configuration, params: FindPetsByTagsParams) -> Result<ResponseContent<FindPetsByTagsSuccess>, Error<FindPetsByTagsError>> {
 
     let uri_str = format!("{}/pet/findByTags", configuration.base_path);

samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/apis/pet_api.rs

@@ -365,6 +365,7 @@ pub async fn find_pets_by_status(configuration: &configuration::Configuration, p
 }
 
 /// Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
+#[deprecated]
 pub async fn find_pets_by_tags(configuration: &configuration::Configuration, params: FindPetsByTagsParams) -> Result<ResponseContent<FindPetsByTagsSuccess>, Error<FindPetsByTagsError>> {
 
     let uri_str = format!("{}/pet/findByTags", configuration.base_path);

samples/client/petstore/rust/reqwest/petstore-async/src/apis/pet_api.rs

@@ -359,6 +359,7 @@ pub async fn find_pets_by_status(configuration: &configuration::Configuration, p
 }
 
 /// Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
+#[deprecated]
 pub async fn find_pets_by_tags(configuration: &configuration::Configuration, params: FindPetsByTagsParams) -> Result<ResponseContent<FindPetsByTagsSuccess>, Error<FindPetsByTagsError>> {
 
     let uri_str = format!("{}/pet/findByTags", configuration.base_path);

samples/client/petstore/rust/reqwest/petstore-avoid-box/src/apis/pet_api.rs

@@ -359,6 +359,7 @@ pub async fn find_pets_by_status(configuration: &configuration::Configuration, p
 }
 
 /// Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
+#[deprecated]
 pub async fn find_pets_by_tags(configuration: &configuration::Configuration, params: FindPetsByTagsParams) -> Result<ResponseContent<FindPetsByTagsSuccess>, Error<FindPetsByTagsError>> {
 
     let uri_str = format!("{}/pet/findByTags", configuration.base_path);

samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/apis/pet_api.rs

@@ -263,6 +263,7 @@ pub fn find_pets_by_status(configuration: &configuration::Configuration, status:
 }
 
 /// Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
+#[deprecated]
 pub fn find_pets_by_tags(configuration: &configuration::Configuration, tags: Vec<String>) -> Result<Vec<models::Pet>, Error<FindPetsByTagsError>> {
     // add a prefix to parameters to efficiently prevent name collisions
     let p_query_tags = tags;

samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/apis/pet_api.rs

@@ -224,6 +224,7 @@ pub fn find_pets_by_status(configuration: &configuration::Configuration, status:
 }
 
 /// Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
+#[deprecated]
 pub fn find_pets_by_tags(configuration: &configuration::Configuration, tags: Vec<String>) -> Result<Vec<models::FooPet>, Error<FindPetsByTagsError>> {
     // add a prefix to parameters to efficiently prevent name collisions
     let p_query_tags = tags;

samples/client/petstore/rust/reqwest/petstore/src/apis/pet_api.rs

@@ -224,6 +224,7 @@ pub fn find_pets_by_status(configuration: &configuration::Configuration, status:
 }
 
 /// Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
+#[deprecated]
 pub fn find_pets_by_tags(configuration: &configuration::Configuration, tags: Vec<String>) -> Result<Vec<models::Pet>, Error<FindPetsByTagsError>> {
     // add a prefix to parameters to efficiently prevent name collisions
     let p_query_tags = tags;