Increase slangc option visibility in docs

Link to slangc command-line reference from readme.
readme. Boost the visiblity of the link in the user-guide.

Consolidates command-line-slangc.md into the user-guide.

Fixes shader-slang#4124

README.md

@@ -40,6 +40,8 @@ Slang binaries are also included in the [Vulkan SDK](https://vulkan.lunarg.com/s
 There are packages built for 32- and 64-bit Windows, as well as 64-bit Ubuntu.
 Each binary release includes the command-line `slangc` compiler, a shared library for the compiler, and the `slang.h` header.
 
+See the [Slang Command Line Options](docs/command-line-slangc-reference.md) for available `slangc` command-line options.
+
 If you want to try out the Slang language without installing anything, a fast and simple way is to use the [Shader Playground](docs/shader-playground.md).
 
 If you would like to build Slang from source, please consult the [build instructions](docs/building.md).

docs/README.md

@@ -9,7 +9,7 @@ Getting Started
 
 The Slang [User's Guide](https://shader-slang.github.io/slang/user-guide/) provides an introduction to the Slang language and its major features, as well as the compilation and reflection API.
 
-There is also documentation specific to using the [`slangc`](command-line-slangc.md) command-line tool.
+There is also documentation specific to using the [slangc](https://shader-slang.github.io/slang/user-guide/compiling.html#command-line-compilation-with-slangc) command-line tool.
 
 Advanced Users
 --------------

docs/nvapi-support.md

@@ -63,7 +63,7 @@ The astute reader may have noticed that the default Slang HLSL prelude *does* co
 #endif
 ```
 
-This means that the *downstream* compiler (such as DXC and FXC) must be able to handle this include. Include paths can be specified for downstream compilers via the [-X mechanism](command-line-slangc.md#downstream-arguments). So for example...
+This means that the *downstream* compiler (such as DXC and FXC) must be able to handle this include. Include paths can be specified for downstream compilers via the [-X mechanism](user-guide/08-compiling.md#downstream-arguments). So for example...
 
 ```
 -Xfxc -IpathTo/nvapi -Xdxc -IpathTo/nvapi