Soft deprecate client, mock, and server modules

Summary:
This is the start of the codemod for https://fb.workplace.com/groups/rust.language/posts/25780668961555042.

It follows the same approach as {D53374511} by adding a comment above the re-exports to identify the correct Buck target to use instead. This way I can codemod all uses by locally changing the comment into a real `#[deprecated = "..."]` attribute, compiling all Rust targets with `-Awarnings -Wdeprecated` in rustflags, parsing the deprecation warnings, and programmatically applying the correct fix.

Note that the deprecation needs to be on a `pub mod` rather than a `pub use` because deprecation on re-exports is not supported by Rust.

Reviewed By: zertosh

Differential Revision: D54332814

fbshipit-source-id: 16358f211032a7b1a701c08d909078b86b53d65f

fb303/thrift/clients/thrift_build.rs

@@ -15,7 +15,7 @@ fn main() {
     let out_dir: &Path = out_dir.as_ref();
     fs::write(
         out_dir.join("cratemap"),
-        "fb303_core crate",
+        "fb303_core crate //fb303/thrift:fb303_core-rust",
     ).expect("Failed to write cratemap");
 
     let conf = {

fb303/thrift/services/thrift_build.rs

@@ -15,7 +15,7 @@ fn main() {
     let out_dir: &Path = out_dir.as_ref();
     fs::write(
         out_dir.join("cratemap"),
-        "fb303_core crate",
+        "fb303_core crate //fb303/thrift:fb303_core-rust",
     ).expect("Failed to write cratemap");
 
     let conf = {

fb303/thrift/thrift_build.rs

@@ -15,7 +15,7 @@ fn main() {
     let out_dir: &Path = out_dir.as_ref();
     fs::write(
         out_dir.join("cratemap"),
-        "fb303_core crate",
+        "fb303_core crate //fb303/thrift:fb303_core-rust",
     ).expect("Failed to write cratemap");
 
     let conf = {

fb303/thrift/types/thrift_build.rs

@@ -15,7 +15,7 @@ fn main() {
     let out_dir: &Path = out_dir.as_ref();
     fs::write(
         out_dir.join("cratemap"),
-        "fb303_core crate",
+        "fb303_core crate //fb303/thrift:fb303_core-rust",
     ).expect("Failed to write cratemap");
 
     let conf = {