Fix clippy::unnecessary_map_or warning

```
error: this `map_or` is redundant
  --> src/cargo.rs:84:41
   |
84 |               need_doctest_in_workspace = cmd!(config.cargo(), "-Z", "help")
   |  _________________________________________^
85 | |                 .read()
86 | |                 .map_or(false, |s| s.contains("doctest-in-workspace"));
   | |______________________________________________________________________^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_map_or
   = note: `-D clippy::unnecessary-map-or` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::unnecessary_map_or)]`
help: use is_ok_and instead
   |
84 ~             need_doctest_in_workspace = cmd!(config.cargo(), "-Z", "help")
85 ~                 .read().is_ok_and(|s| s.contains("doctest-in-workspace"));
   |

error: this `map_or` is redundant
   --> src/context.rs:156:24
    |
156 |                       if cmd!("rustup", "toolchain", "list")
    |  ________________________^
157 | |                         .read()
158 | |                         .map_or(false, |t| t.contains(toolchain))
    | |_________________________________________________________________^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_map_or
help: use is_ok_and instead
    |
156 ~                     if cmd!("rustup", "toolchain", "list")
157 +                         .read().is_ok_and(|t| t.contains(toolchain))
    |

error: this `map_or` is redundant
   --> src/main.rs:701:24
    |
701 |                       if p.file_name()
    |  ________________________^
702 | |                         .map_or(false, |f| f == "incremental" || f == ".fingerprint" || f == "out")
    | |___________________________________________________________________________________________________^ help: use is_some_and instead: `p.file_name().is_some_and(|f| f == "incremental" || f == ".fingerprint" || f == "out")`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_map_or

error: this `map_or` is redundant
    --> src/main.rs:1313:20
     |
1313 |                 if p.extension().map_or(false, |e| e == "rs") {
     |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use is_some_and instead: `p.extension().is_some_and(|e| e == "rs")`
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_map_or
```

src/cargo.rs

@@ -83,7 +83,7 @@ impl Workspace {
         if doctests {
             need_doctest_in_workspace = cmd!(config.cargo(), "-Z", "help")
                 .read()
-                .map_or(false, |s| s.contains("doctest-in-workspace"));
+                .is_ok_and(|s| s.contains("doctest-in-workspace"));
         }
 
         let target_dir =

src/context.rs

@@ -155,7 +155,7 @@ impl Context {
                     let toolchain = sysroot.file_name().unwrap();
                     if cmd!("rustup", "toolchain", "list")
                         .read()
-                        .map_or(false, |t| t.contains(toolchain))
+                        .is_ok_and(|t| t.contains(toolchain))
                     {
                         // If toolchain is installed from rustup and llvm-tools-preview is not installed,
                         // suggest installing llvm-tools-preview via rustup.

src/main.rs

@@ -699,7 +699,7 @@ fn object_files(cx: &Context) -> Result<Vec<OsString>> {
                 let p = e.path();
                 if p.is_dir() {
                     if p.file_name()
-                        .map_or(false, |f| f == "incremental" || f == ".fingerprint" || f == "out")
+                        .is_some_and(|f| f == "incremental" || f == ".fingerprint" || f == "out")
                     {
                         // Ignore incremental compilation related files and output from build scripts.
                         return false;
@@ -1310,7 +1310,7 @@ fn resolve_excluded_paths(cx: &Context) -> Vec<Utf8PathBuf> {
         for _ in WalkDir::new(excluded).into_iter().filter_entry(|e| {
             let p = e.path();
             if !p.is_dir() {
-                if p.extension().map_or(false, |e| e == "rs") {
+                if p.extension().is_some_and(|e| e == "rs") {
                     let p = p.strip_prefix(&cx.ws.metadata.workspace_root).unwrap_or(p);
                     excluded_path.push(p.to_owned().try_into().unwrap());
                 }