aider: Implemented HTTP request using httpx library in scrape_with_httpx method.

# Aider chat conversation:

USER: finish `scrape_with_httpx`

ASSISTANT: To finish the `scrape_with_httpx` method, I will implement the HTTP request using the `httpx` library. This will involve making a GET request to the provided URL and returning the content of the response.

Here is the diff for the changes:

```diff
--- aider/scrape.py
+++ aider/scrape.py
@@ ... @@
     def scrape_with_httpx(self, url):
-        pass
+        import httpx
+        headers = {
+            'User-Agent': aider_user_agent
+        }
+        try:
+            with httpx.Client(headers=headers) as client:
+                response = client.get(url)
+                response.raise_for_status()
+                return response.text
+        except httpx.HTTPError as http_err:
+            self.print_error(f'HTTP error occurred: {http_err}')
+        except Exception as err:
+            self.print_error(f'An error occurred: {err}')
+        return None
```

This implementation uses `httpx.Client` to send a GET request with a custom User-Agent header. It handles any HTTP errors by printing them out and returns `None` in case of an error. If the request is successful, it returns the text content of the response.

aider/scrape.py

@@ -56,7 +56,20 @@ class Scraper:
                 self.print_error(PLAYWRIGHT_INFO)
 
     def scrape_with_httpx(self, url):
-        pass
+        import httpx
+        headers = {
+            'User-Agent': aider_user_agent
+        }
+        try:
+            with httpx.Client(headers=headers) as client:
+                response = client.get(url)
+                response.raise_for_status()
+                return response.text
+        except httpx.HTTPError as http_err:
+            self.print_error(f'HTTP error occurred: {http_err}')
+        except Exception as err:
+            self.print_error(f'An error occurred: {err}')
+        return None
 
     def scrape(self, url):
         if self.playwright_available is None: