Bump MSRV to 1.88.0 (#4367)

## Motivation and Context
Bumps MSRV to 1.88.0

## Description
Although the number of files changed is large, the changes themselves
are straightforward. During MSRV upgrade to 1.88.0, one of the clippy
warnings enforced is `clippy::uninlined_format_args`, i.e. suggesting to
update
```
format!("{}", a);
```
to
```
format!("{a}");
```
The PR swept through the codebase and updated almost all the
occurrences, except for:
- codegen-client (suppressed the following)
-
[RequestBindingGenerator](https://github.com/smithy-lang/smithy-rs/pull/4367/files#diff-fea7e7ebc2f668be75ee8e15dd463bd38064b416eea4c0d272e17ce52e2e7598R138-R142)
-
[‎EndpointTraitBindingGenerator](https://github.com/smithy-lang/smithy-rs/pull/4367/files#diff-bf24c9ba358f747e62b6603c3ddfae91340a9971c41b268a148f705dfface9deR92-R96)
- codegen-server
  - #4366

## Testing
- CI

## Checklist
<!--- If a checkbox below is not applicable, then please DELETE it
rather than leaving it unchecked -->
- [x] For changes to the smithy-rs codegen or runtime crates, I have
created a changelog entry Markdown file in the `.changelog` directory,
specifying "client," "server," or both in the `applies_to` key.
- [x] For changes to the AWS SDK, generated SDK code, or SDK runtime
crates, I have created a changelog entry Markdown file in the
`.changelog` directory, specifying "aws-sdk-rust" in the `applies_to`
key.

----

_By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice._

Author: ysaito1001

.changelog/1761582203.md

@@ -0,0 +1,14 @@
+---
+applies_to:
+- aws-sdk-rust
+- client
+- server
+authors:
+- ysaito1001
+references:
+- smithy-rs#4367
+breaking: true
+new_feature: false
+bug_fix: false
+---
+Upgrade MSRV to Rust 1.88.0.

.github/workflows/ci.yml

@@ -33,7 +33,7 @@ on:
         required: false
 
 env:
-  rust_version: 1.86.0
+  rust_version: 1.88.0
   rust_toolchain_components: clippy,rustfmt
   ENCRYPTED_DOCKER_PASSWORD: ${{ secrets.ENCRYPTED_DOCKER_PASSWORD }}
   DOCKER_LOGIN_TOKEN_PASSPHRASE: ${{ secrets.DOCKER_LOGIN_TOKEN_PASSPHRASE }}

.github/workflows/claim-crate-names.yml

@@ -10,7 +10,7 @@ concurrency:
   cancel-in-progress: true
 
 env:
-  rust_version: 1.86.0
+  rust_version: 1.88.0
 
 name: Claim unpublished crate names on crates.io
 run-name: ${{ github.workflow }}

.github/workflows/github-pages.yml

@@ -8,7 +8,7 @@ on:
 name: Update GitHub Pages
 
 env:
-  rust_version: 1.86.0
+  rust_version: 1.88.0
 
 # Allow only one doc pages build to run at a time for the entire smithy-rs repo
 concurrency:

.github/workflows/release.yml

@@ -10,7 +10,7 @@ concurrency:
   cancel-in-progress: true
 
 env:
-  rust_version: 1.86.0
+  rust_version: 1.88.0
 
 name: Release smithy-rs
 on:

.github/workflows/update-sdk-next.yml

@@ -46,7 +46,7 @@ jobs:
     - name: Set up Rust
       uses: dtolnay/rust-toolchain@master
       with:
-        toolchain: 1.86.0
+        toolchain: 1.88.0
     - name: Delete old SDK
       run: |
     - name: Generate a fresh SDK

aws/codegen-aws-sdk/src/main/kotlin/software/amazon/smithy/rustsdk/AwsFluentClientDecorator.kt

@@ -186,7 +186,7 @@ private class AwsFluentClientRetryPartition(private val codegenContext: ClientCo
                     rustTemplate(
                         """
                         let default_retry_partition = match config.region() {
-                            Some(region) => #{Cow}::from(format!("{default_retry_partition}-{}", region)),
+                            Some(region) => #{Cow}::from(format!("{default_retry_partition}-{region}")),
                             None => #{Cow}::from(default_retry_partition),
                         };
                         """,

aws/rust-runtime/Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "aws-config"
-version = "1.8.9"
+version = "1.8.10"
 authors = [
     "AWS Rust SDK Team <[email protected]>",
     "Russell Cohen <[email protected]>",