Added faq entry

docs/faq.md

@@ -16,6 +16,7 @@ Working without git means that GPT might drastically change your code without an
 Aider tries to provide safety using git in a few ways:
 
   - It asks to create a git repo if you launch it in a directory without one.
+  - When you add a file to the chat, aider asks permission to add it to the git repo if needed.
   - At launch and before sending requests to GPT, aider checks if the repo is dirty and offers to commit those changes for you. This way, the GPT changes will be applied to a clean repo and won't be intermingled with your own changes.
   - After GPT changes your code, aider commits those changes with a descriptive commit message.
 
@@ -68,6 +69,32 @@ This minimizes your use of the context window, as well as costs.
 | gpt-4             |  8k tokens | diffs | 8k tokens | ~32k bytes | yes |
 | gpt-4-32k         | 32k tokens | diffs | 32k tokens  | ~128k bytes | yes |
 
+## Aider isn't editing my files?
+
+This usually happens because GPT is not specifying the edits
+to make in the format that aider expects.
+GPT-3.5 is especially prone to disobeying the system prompt instructions in this manner, but it also happens with GPT-4.
+
+Aider makes every effort to get GPT to conform, and works hard to deal with
+replies that are "almost" correctly formatted.
+If Aider detects an improperly formatted reply, it gives GPT feedback to try again.
+Also, before each release new versions of aider are
+[benchmarked](https://aider.chat/docs/benchmarks.html).
+This helps prevent regressions in the code editing
+performance of GPT that could have been inadvertantly
+introduced.
+
+But sometimes GPT just won't cooperate.
+In these cases, here are some things you might try:
+
+  - Just ask it to try again. Explain the problem with the response if you can. Here is some suggested language which will be familiar to GPT based on its system prompt.
+    - With GPT-3.5, you could say something like "Send me back the new code as a properly formatted **file listing**".
+    - With GPT-4, you could say something like "Format those code changes properly as an **edit block**".
+    - "Don't skip code and replace it with comments, send me back all the code!"
+    - Etc...
+  - Use `/drop` to remove files from the chat session which aren't needed for the task at hand. This will reduce distractions and may help GPT produce properly formatted edits.
+  - Use `/clear` to remove the conversation history, again to help GPT focus.
+
 ## Can I use aider with other LLMs, local LLMs, etc?
 
 Aider does not officially support use with LLMs other than OpenAI's gpt-3.5-turbo and gpt-4
@@ -128,6 +155,8 @@ and
 look like relevant tools to serve local models via a compatible API:
 
 
+
+
 ## Can I change the system prompts that aider uses?
 
 Aider is set up to support different system prompts and edit formats