docs: Use relative paths (#1636)

* changed https links

* removed extra info in link

docs/extending.md

@@ -27,7 +27,7 @@ The lazy-only layer is a major item on our 2025 roadmap, and hope to be able to
 the "interchange" level into that one.
 
 Libraries for which we have full support can benefit from the whole
-[Narwhals API](https://narwhals-dev.github.io/narwhals/api-reference/).
+[Narwhals API](./api-reference/index.md).
 
 For example:
 

docs/index.md

@@ -14,17 +14,17 @@ Extremely lightweight and extensible compatibility layer between dataframe libra
 
 Seamlessly support all, without depending on any!
 
-- ✅ **Just use** [a subset of **the Polars API**](https://narwhals-dev.github.io/narwhals/api-reference/), no need to learn anything new
+- ✅ **Just use** [a subset of **the Polars API**](./api-reference/index.md), no need to learn anything new
 - ✅ **Zero dependencies**, Narwhals only uses what
   the user passes in so your library can stay lightweight
 - ✅ Separate **lazy** and eager APIs, use **expressions**
 - ✅ Support pandas' complicated type system and index, without
   either getting in the way
 - ✅ **100% branch coverage**, tested against pandas and Polars nightly builds
-- ✅ **Negligible overhead**, see [overhead](https://narwhals-dev.github.io/narwhals/overhead/)
-- ✅ Let your IDE help you thanks to **full static typing**, see [typing](https://narwhals-dev.github.io/narwhals/api-reference/typing/)
+- ✅ **Negligible overhead**, see [overhead](./overhead.md/)
+- ✅ Let your IDE help you thanks to **full static typing**, see [`narwhals.typing`][]
 - ✅ **Perfect backwards compatibility policy**,
-  see [stable api](https://narwhals-dev.github.io/narwhals/backcompat/) for how to opt-in
+  see [stable api](./backcompat.md/) for how to opt-in
 
 ## Who's this for?
 

narwhals/stable/v1/__init__.py

@@ -2025,7 +2025,7 @@ def from_native(
             - `True`: only convert to Narwhals if `native_object` is eager or has
               interchange-level support in Narwhals
 
-            See [interchange-only support](https://narwhals-dev.github.io/narwhals/extending/#interchange-only-support)
+            See [interchange-only support](../extending.md/#interchange-only-support)
             for more details.
         series_only: Whether to only allow Series:
 
@@ -2181,7 +2181,7 @@ def narwhalify(
             - `True`: only convert to Narwhals if `native_object` is eager or has
               interchange-level support in Narwhals
 
-            See [interchange-only support](https://narwhals-dev.github.io/narwhals/extending/#interchange-only-support)
+            See [interchange-only support](../extending.md/#interchange-only-support)
             for more details.
         series_only: Whether to only allow Series:
 

narwhals/translate.py

@@ -361,7 +361,7 @@ def from_native(
             - `True`: only convert to Narwhals if `native_object` is eager or has
               interchange-level support in Narwhals
 
-            See [interchange-only support](https://narwhals-dev.github.io/narwhals/extending/#interchange-only-support)
+            See [interchange-only support](../extending.md/#interchange-only-support)
             for more details.
         series_only: Whether to only allow Series:
 
@@ -869,7 +869,7 @@ def narwhalify(
             - `True`: only convert to Narwhals if `native_object` is eager or has
               interchange-level support in Narwhals
 
-            See [interchange-only support](https://narwhals-dev.github.io/narwhals/extending/#interchange-only-support)
+            See [interchange-only support](../extending.md/#interchange-only-support)
             for more details.
         series_only: Whether to only allow Series: