Use anyhow more idiomatically (#31052)

https://github.com/zed-industries/zed/issues/30972 brought up another
case where our context is not enough to track the actual source of the
issue: we get a general top-level error without inner error.

The reason for this was `.ok_or_else(|| anyhow!("failed to read HEAD
SHA"))?; ` on the top level.

The PR finally reworks the way we use anyhow to reduce such issues (or
at least make it simpler to bubble them up later in a fix).
On top of that, uses a few more anyhow methods for better readability.

* `.ok_or_else(|| anyhow!("..."))`, `map_err` and other similar error
conversion/option reporting cases are replaced with `context` and
`with_context` calls
* in addition to that, various `anyhow!("failed to do ...")` are
stripped with `.context("Doing ...")` messages instead to remove the
parasitic `failed to` text
* `anyhow::ensure!` is used instead of `if ... { return Err(...); }`
calls
* `anyhow::bail!` is used instead of `return Err(anyhow!(...));`

Release Notes:

- N/A

crates/git_hosting_providers/src/git_hosting_providers.rs

@@ -3,7 +3,8 @@ mod settings;
 
 use std::sync::Arc;
 
-use anyhow::{Result, anyhow};
+use anyhow::Context as _;
+use anyhow::Result;
 use git::GitHostingProviderRegistry;
 use git::repository::GitRepository;
 use gpui::App;
@@ -58,7 +59,7 @@ pub fn get_host_from_git_remote_url(remote_url: &str) -> Result<String> {
             .ok()
             .and_then(|remote_url| remote_url.host_str().map(|host| host.to_string()))
     })
-    .ok_or_else(|| anyhow!("URL has no host"))
+    .context("URL has no host")
 }
 
 #[cfg(test)]

crates/git_hosting_providers/src/providers/chromium.rs

@@ -1,7 +1,7 @@
 use std::str::FromStr;
 use std::sync::{Arc, LazyLock};
 
-use anyhow::{Context, Result, bail};
+use anyhow::{Context as _, Result, bail};
 use async_trait::async_trait;
 use futures::AsyncReadExt;
 use git::{

crates/git_hosting_providers/src/providers/codeberg.rs

@@ -1,7 +1,7 @@
 use std::str::FromStr;
 use std::sync::Arc;
 
-use anyhow::{Context, Result, bail};
+use anyhow::{Context as _, Result, bail};
 use async_trait::async_trait;
 use futures::AsyncReadExt;
 use gpui::SharedString;

crates/git_hosting_providers/src/providers/github.rs

@@ -1,7 +1,7 @@
 use std::str::FromStr;
 use std::sync::{Arc, LazyLock};
 
-use anyhow::{Context, Result, bail};
+use anyhow::{Context as _, Result, bail};
 use async_trait::async_trait;
 use futures::AsyncReadExt;
 use gpui::SharedString;