doc: move cmake -B build -LH up in Unix build docs

Author: bufo24

doc/build-unix.md

@@ -9,6 +9,10 @@ To Build
 
 ```bash
 cmake -B build
+```
+Run `cmake -B build -LH` to see the full list of available options.
+
+```bash
 cmake --build build    # Append "-j N" for N parallel jobs
 cmake --install build  # Optional
 ```
@@ -156,13 +160,6 @@ In this case there is no dependency on SQLite.
 
 Mining is also possible in disable-wallet mode using the `getblocktemplate` RPC call.
 
-Additional Configure Flags
---------------------------
-A list of additional configure flags can be displayed with:
-
-    cmake -B build -LH
-
-
 Setup and Build Example: Arch Linux
 -----------------------------------
 This example lists the steps necessary to setup and build a command line only distribution of the latest changes on Arch Linux: