[IMP] developer/howtos: encourage linters more

There have been complaints of newbies not setting up their linters
therefore let's emphasize their use/setup more in the tutorial and hope
for the best.

Part-of: odoo/documentation#1146

content/developer/howtos/rdtraining/02_setup.rst

@@ -337,6 +337,18 @@ For Python, we use PEP8 with these options ignored:
 
 For JavaScript, we use ESLint and you can find a `configuration file example here`_.
 
+If you do not know how to set up a linter:
+
+- `Here is an explanation of how to set up a Python linter in VSCode <https://code.visualstudio.com/docs/python/linting>`_. There are multiple
+  linter options you are free to choose from, but `Flake8 <https://pypi.org/project/flake8/>`_ is a popular choice.
+- To setup ESLint in VSCode, you must download the `ESLint extension`_ and follow its instructions
+  for installing ESLint. Don't forget to create and set up the `.eslintrc` file to follow the
+  configuration file mentioned above.
+- Another useful VSCode plugin is `Trailing Spaces`_ to quickly notice trailing spaces while
+  you're working.
+
+.. _Trailing Spaces: https://marketplace.visualstudio.com/items?itemName=shardulm94.trailing-spaces
+.. _ESLint extension: https://marketplace.visualstudio.com/items?itemName=dbaeumer.vscode-eslint
 .. _configuration file example here: https://github.com/odoo/odoo/wiki/Javascript-coding-guidelines#use-a-linter
 .. _VSCode: https://code.visualstudio.com/
 .. _VSCodium: https://vscodium.com/

content/developer/howtos/rdtraining/16_guidelines_pr.rst

@@ -18,9 +18,9 @@ to improve the quality of the Odoo Apps code.
 
 .. exercise:: Polish your code.
 
-    Refactor your code to respect the coding guidelines. Don't forget to respect the module
-    structure, the variable names, the method name convention, the model attribute order and the
-    xml ids.
+    Refactor your code to respect the coding guidelines. Don't forget to run your linter and
+    respect the module structure, the variable names, the method name convention, the model
+    attribute order and the xml ids.
 
 Your first Pull Request (PR)
 ============================