docs: fix rustup cmd for adding rust-analyzer (#18605)

Important to specify the patch version so rust-analyzer component is
picked up correctly by tools like helix

Author: Jefffrey

docs/source/contributor-guide/development_environment.md

@@ -77,7 +77,7 @@ DataFusion is written in Rust and it uses a standard rust toolkit:
 
 - `rustup update stable` DataFusion generally uses the latest stable release of Rust, though it may lag when new Rust toolchains release
   - See which toolchain is currently pinned in the [`rust-toolchain.toml`](https://github.com/apache/datafusion/blob/main/rust-toolchain.toml) file
-  - This can cause issues such as not having the rust-analyzer component installed for the specified toolchain, in which case just install it manually, e.g. `rustup component add --toolchain 1.88 rust-analyzer`
+  - This can cause issues such as not having the rust-analyzer component installed for the specified toolchain, in which case just install it manually, e.g. `rustup component add --toolchain 1.88.0 rust-analyzer`
 - `cargo build`
 - `cargo fmt` to format the code
 - etc.