feat: Add documentation for infinite output

aider/website/docs/more/infinite-output.md

@@ -0,0 +1,48 @@
+---
+parent: More info
+nav_order: 920
+description: Aider can handle "infinite output" from models that support prefill.
+---
+
+# Infinite output
+
+LLM providers limit how much output a model can generate from a single request.
+This is usually called the output token limit.
+
+Aider is able to work around this limit with models that support
+"prefilling" the assistant response.
+When you use aider with a model that supports prefill, you will see
+"infinite output" noted in the announcement lines displayed at launch:
+
+```
+Aider v0.58.0
+Main model: claude-3-5-sonnet-20240620 with diff edit format, prompt cache, infinite output
+```
+
+Models that support prefill can be primed to think they started their response
+with a specific piece of text.
+You can put words in their mouth, and they will continue generating
+text from that point forward.
+
+When aider is collecting code edits from a model and
+it hits the output token limit,
+aider simply initiates another LLM request with the partial
+response prefilled.
+This prompts the model to continue where it left off,
+generating more of the desired response.
+This prefilling of the partially completed response can be repeated,
+allowing for very long outputs.
+Joining the text across these output limit boundaries 
+requires some heuristics, but is typically fairly reliable.
+
+Aider supports "infinite output" for models that support "prefill",
+such as:
+
+<!--[[[cog
+# TODO: list the models
+cog.out(text)
+]]]-->
+
+<!--[[[end]]]-->
+
+