Add a way to import ssh host names from the ssh config (#30926)

Closes https://github.com/zed-industries/zed/issues/20016

Use `"read_ssh_config": false` to disable the new behavior.

Release Notes:

- Added a way to import ssh host names from the ssh config

---------

Co-authored-by: Cole Miller <m@cole-miller.net>

crates/recent_projects/src/ssh_config.rs

@@ -0,0 +1,96 @@
+use std::collections::BTreeSet;
+
+pub fn parse_ssh_config_hosts(config: &str) -> BTreeSet<String> {
+    let mut hosts = BTreeSet::new();
+    let mut needs_another_line = false;
+    for line in config.lines() {
+        let line = line.trim_start();
+        if let Some(line) = line.strip_prefix("Host") {
+            match line.chars().next() {
+                Some('\\') => {
+                    needs_another_line = true;
+                }
+                Some('\n' | '\r') => {
+                    needs_another_line = false;
+                }
+                Some(c) if c.is_whitespace() => {
+                    parse_hosts_from(line, &mut hosts);
+                }
+                Some(_) | None => {
+                    needs_another_line = false;
+                }
+            };
+
+            if needs_another_line {
+                parse_hosts_from(line, &mut hosts);
+                needs_another_line = line.trim_end().ends_with('\\');
+            } else {
+                needs_another_line = false;
+            }
+        } else if needs_another_line {
+            needs_another_line = line.trim_end().ends_with('\\');
+            parse_hosts_from(line, &mut hosts);
+        } else {
+            needs_another_line = false;
+        }
+    }
+
+    hosts
+}
+
+fn parse_hosts_from(line: &str, hosts: &mut BTreeSet<String>) {
+    hosts.extend(
+        line.split_whitespace()
+            .filter(|field| !field.starts_with("!"))
+            .filter(|field| !field.contains("*"))
+            .filter(|field| !field.is_empty())
+            .map(|field| field.to_owned()),
+    );
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_thank_you_bjorn3() {
+        let hosts = "
+            Host *
+              AddKeysToAgent yes
+              UseKeychain yes
+              IdentityFile ~/.ssh/id_ed25519
+
+            Host whatever.*
+            User another
+
+            Host !not_this
+            User not_me
+
+            Host something
+        HostName whatever.tld
+
+        Host linux bsd host3
+          User bjorn
+
+        Host rpi
+          user rpi
+          hostname rpi.local
+
+        Host \
+               somehost \
+        anotherhost
+        Hostname 192.168.3.3";
+
+        let expected_hosts = BTreeSet::from_iter([
+            "something".to_owned(),
+            "linux".to_owned(),
+            "host3".to_owned(),
+            "bsd".to_owned(),
+            "rpi".to_owned(),
+            "somehost".to_owned(),
+            "anotherhost".to_owned(),
+        ]);
+
+        assert_eq!(expected_hosts, parse_ssh_config_hosts(hosts));
+    }
+}