Fix markup (paths are not code)

guidelines/hierarchy.md

 ### src ###
 
 Everything that is supposed to be (directly or in some "built" form)
-deployed on the target host goes under `src`.
+deployed on the target host goes under *src*.
 
 Under this folder, it makes sense to have files divided in sub-folders
 named reminiscent to the target paths.  For example, host configuration
-files should be under `src/etc`, library source files under `src/lib`,
-future binaries under `src/bin`, future manpages to `src/man`...
+files should be under *src/etc*, library source files under *src/lib*,
+future binaries under *src/bin*, future manpages to *src/man*...
 
 Note that it does not matter whether there is some significant build
 procedure to happen; it's OK if most of the files here are just verbatim
     │   │   ├── TF_RUN          #
     │   │   ├── oracle          #   hierarchy is influenced by TFKit
     │   │   │   └── ...         #   which itself is actually embedded
-    │   │   └── test            #   under `utils` directory below
+    │   │   └── test            #   under *utils* directory below
     │   │       └── ...         # /
     │   └── ...                 #
     └── utils           # \