Add links to ecosystem check result (#5631)

## Summary

Add links for ecosystem check result. This is useful for developers to
quickly check the added/removed violations with a single click.

There are a few downsides of this approach:
* Syntax highlighting is not available for the output
* Content length is increased because of the additional anchor tags

## Test Plan

`python scripts/check_ecosystem.py ./target/debug/ruff ../ruff-test/target/debug/ruff`

<details><summary>Example Output:</summary>

ℹ️ ecosystem check **detected changes**. (+6, -0, 0 error(s))

<details><summary>airflow (+1, -0)</summary>
<p>

<pre>
+ <a
href='https://github.com/apache/airflow/blob/main/dev/breeze/src/airflow_breeze/commands/release_management_commands.py#L654'>dev/breeze/src/airflow_breeze/commands/release_management_commands.py:654:25:</a>
PERF401 Use a list comprehension to create a transformed list
</pre>

</p>
</details>
<details><summary>bokeh (+3, -0)</summary>
<p>

<pre>
+ <a
href='https://github.com/bokeh/bokeh/blob/branch-3.2/src/bokeh/model/model.py#L315'>src/bokeh/model/model.py:315:17:</a>
PERF401 Use a list comprehension to create a transformed list
+ <a
href='https://github.com/bokeh/bokeh/blob/branch-3.2/src/bokeh/resources.py#L470'>src/bokeh/resources.py:470:25:</a>
PERF401 Use a list comprehension to create a transformed list
+ <a
href='https://github.com/bokeh/bokeh/blob/branch-3.2/src/bokeh/sphinxext/bokeh_sampledata_xref.py#L134'>src/bokeh/sphinxext/bokeh_sampledata_xref.py:134:17:</a>
PERF401 Use a list comprehension to create a transformed list
</pre>

</p>
</details>
<details><summary>zulip (+2, -0)</summary>
<p>

<pre>
+ <a
href='https://github.com/zulip/zulip/blob/main/zerver/actions/create_user.py#L197'>zerver/actions/create_user.py:197:17:</a>
PERF401 Use a list comprehension to create a transformed list
+ <a
href='https://github.com/zulip/zulip/blob/main/zerver/lib/markdown/__init__.py#L2412'>zerver/lib/markdown/__init__.py:2412:13:</a>
PERF401 Use a list comprehension to create a transformed list
</pre>

</p>
</details>

</details>

---------

Co-authored-by: konsti <konstin@mailbox.org>

scripts/check_ecosystem.py

@@ -82,6 +82,17 @@ class Repository(NamedTuple):
 
         yield Path(checkout_dir)
 
+    def url_for(self: Self, path: str, lnum: int | None = None) -> str:
+        """Return the GitHub URL for the given path and line number, if given."""
+        # Default to main branch
+        url = (
+            f"https://github.com/{self.org}/{self.repo}"
+            f"/blob/{self.ref or 'main'}/{path}"
+        )
+        if lnum:
+            url += f"#L{lnum}"
+        return url
+
 
 REPOSITORIES: list[Repository] = [
     Repository("apache", "airflow", "main", select="ALL"),
@@ -272,6 +283,11 @@ def read_projects_jsonl(projects_jsonl: Path) -> dict[tuple[str, str], Repositor
     return repositories
 
 
+DIFF_LINE_RE = re.compile(
+    r"^(?P<pre>[+-]) (?P<inner>(?P<path>[^:]+):(?P<lnum>\d+):\d+:) (?P<post>.*)$",
+)
+
+
 T = TypeVar("T")
 
 
@@ -352,18 +368,27 @@ async def main(
                 print("<p>")
                 print()
 
-                diff_str = "\n".join(diff)
+                repo = repositories[(org, repo)]
+                diff_lines = list(diff)
 
-                print("```diff")
-                print(diff_str)
-                print("```")
+                print("<pre>")
+                for line in diff_lines:
+                    match = DIFF_LINE_RE.match(line)
+                    if match is None:
+                        print(line)
+                        continue
+
+                    pre, inner, path, lnum, post = match.groups()
+                    url = repo.url_for(path, int(lnum))
+                    print(f"{pre} <a href='{url}'>{inner}</a> {post}")
+                print("</pre>")
 
                 print()
                 print("</p>")
                 print("</details>")
 
                 # Count rule changes
-                for line in diff_str.splitlines():
+                for line in diff_lines:
                     # Find rule change for current line or construction
                     # + <rule>/<path>:<line>:<column>: <rule_code> <message>
                     matches = re.search(r": ([A-Z]{1,4}[0-9]{3,4})", line)