Refine osdk doc

docs/src/osdk/guide/create-project.md

@@ -39,11 +39,11 @@ contains the following contents:
 
 ```text
 myos/
-  src/
-    lib.rs
-  Cargo.toml
-  OSDK.toml
-  rust-toolchain.toml
+├── Cargo.toml
+├── OSDK.toml
+├── rust-toolchain.toml
+└── src/
+    └── lib.rs
 ```
 
 ### `src/lib.rs`

docs/src/osdk/guide/work-in-workspace.md

@@ -36,17 +36,17 @@ The generated directory structure will be as follows:
 
 ```text
 myworkspace/
-  Cargo.toml
-  OSDK.toml
-  rust-toolchain.toml
-  myos/
-    src/
-      lib.rs
-    Cargo.toml
-  mymodule/
-    src/    
-      lib.rs
-    Cargo.toml
+  ├── Cargo.toml
+  ├── OSDK.toml
+  ├── rust-toolchain.toml
+  ├── myos/
+  │   ├── Cargo.toml
+  │   └── src/
+  │       └── lib.rs
+  └── mymodule/
+      ├── Cargo.toml
+      └── src/
+          └── lib.rs
 ```
 
 In addition to the two projects,