Replace number of threads querying with $(...) notation

This allows adding the rst-backticks check again

Author: urfeex

.pre-commit-config.yaml

@@ -128,7 +128,7 @@ repos:
   - repo: https://github.com/pre-commit/pygrep-hooks
     rev: v1.10.0
     hooks:
-      # - id: rst-backticks  # this triggers for backticks inside code-blocks, as well
+      - id: rst-backticks
       - id: rst-directive-colons
       - id: rst-inline-touching-normal
 

ur_robot_driver/doc/installation/real_time.rst

@@ -209,7 +209,7 @@ Now you can build the kernel. This will take some time...
 
 .. code-block:: console
 
-   $ make -j `getconf _NPROCESSORS_ONLN` deb-pkg
+   $ make -j $(getconf _NPROCESSORS_ONLN) deb-pkg
 
 After building, install the ``linux-headers`` and ``linux-image`` packages in the parent folder (only
 the ones without the ``-dbg`` in the name)