docs: fix ordering of preprocess

Signed-off-by: James Harmison <jharmison@gmail.com>

Author: solacelost

docs/buildah-build.1.md

@@ -225,13 +225,6 @@ Containerfiles ending with a ".in" suffix will be preprocessed via cpp(1). This
 Note: You can also set default CPPFLAGS by setting the BUILDAH\_CPPFLAGS
 environment variable (e.g., `export BUILDAH_CPPFLAGS="-DDEBUG"`).
 
-**--preprocess**
-
-If specified, will always attempt to use the C Preprocessor cpp(1),
-even if the Containerfile doesn't end with the ".in" suffix.
-Note: You can also configure this behavior by setting the BUILDAH\_PREPROCESS
-environment variable to `1`, `true`, or `yes`.
-
 **--cpu-period**=*0*
 
 Set the CPU period for the Completely Fair Scheduler (CFS), which is a
@@ -827,6 +820,13 @@ The `buildah build` command allows building images for all Linux architectures,
 
 **NOTE:** The `--platform` option may not be used in combination with the `--arch`, `--os`, or `--variant` options.
 
+**--preprocess**
+
+If specified, will always attempt to use the C Preprocessor cpp(1),
+even if the Containerfile doesn't end with the ".in" suffix.
+Note: You can also configure this behavior by setting the BUILDAH\_PREPROCESS
+environment variable to `1`, `true`, or `yes`.
+
 **--pull**
 
 Pull image policy. If not specified, the default is **missing**. If an explicit