Fixes/adjustments to Fuchsia doc walkthrough

src/doc/rustc/src/platform-support/fuchsia.md

@@ -125,13 +125,20 @@ during compilation:
 [target.x86_64-fuchsia]
 
 rustflags = [
-    "-Lnative", "<SDK_PATH>/arch/x64/sysroot/lib",
-    "-Lnative", "<SDK_PATH>/arch/x64/lib"
+    "-Lnative=<SDK_PATH>/arch/x64/lib",
+    "-Lnative=<SDK_PATH>/arch/x64/sysroot/lib"
 ]
 ```
 
 *Note: Make sure to fill out `<SDK_PATH>` with the path to the downloaded [Fuchsia SDK].*
 
+These options configure the following:
+
+* `-Lnative=${SDK_PATH}/arch/${ARCH}/lib`: Link against Fuchsia libraries from
+  the SDK
+* `-Lnative=${SDK_PATH}/arch/${ARCH}/sysroot/lib`: Link against Fuchsia kernel
+  libraries from the SDK
+
 In total, our new project will look like:
 
 **Current directory structure**
@@ -368,6 +375,7 @@ language called CML. The Fuchsia devsite contains an [overview of CML] and a
 }
 ```
 
+**Current directory structure**
 ```txt
 hello_fuchsia/
 ┗━ pkg/
@@ -386,6 +394,9 @@ ${SDK_PATH}/tools/${ARCH}/cmc compile \
     -o pkg/meta/hello_fuchsia.cm
 ```
 
+*Note: `--includepath` tells the compiler where to look for `include`s from our CML.
+In our case, we're only using `syslog/client.shard.cml`.*
+
 **Current directory structure**
 ```txt
 hello_fuchsia/
@@ -397,19 +408,16 @@ hello_fuchsia/
    ┗━ hello_fuchsia.cml
 ```
 
-*Note: `--includepath` tells the compiler where to look for `include`s from our CML.
-In our case, we're only using `syslog/client.shard.cml`.*
-
 ### Building a Fuchsia package
 
 Next, we'll build a package manifest as defined by our manifest:
 
 ```sh
 ${SDK_PATH}/tools/${ARCH}/pm \
-    -o hello_fuchsia_manifest \
+    -o pkg/hello_fuchsia_manifest \
     -m pkg/hello_fuchsia.manifest \
     build \
-    -output-package-manifest hello_fuchsia_package_manifest
+    -output-package-manifest pkg/hello_fuchsia_package_manifest
 ```
 
 This will produce `pkg/hello_fuchsia_manifest/` which is a package manifest we can
@@ -469,15 +477,15 @@ We can publish our new package to that repository with:
 
 ```sh
 ${SDK_PATH}/tools/${ARCH}/pm publish \
-    -repo repo \
-    -lp -f <(echo "hello_fuchsia_package_manifest")
+    -repo pkg/repo \
+    -lp -f <(echo "pkg/hello_fuchsia_package_manifest")
 ```
 
 Then we can add the repository to `ffx`'s package server as `hello-fuchsia` using:
 
 ```sh
 ${SDK_PATH}/tools/${ARCH}/ffx repository add-from-pm \
-    repo \
+    pkg/repo \
     -r hello-fuchsia
 ```