Merge branch 'fix-update-ruby-doc' into 'master'

Fix for update 8.10-to-8.11.md doc.

## What does this MR do?

Fixed a typo in the docs to update Ruby.

See merge request !5941

doc/update/8.10-to-8.11.md

@@ -28,7 +28,7 @@ You can check which version you are running with `ruby -v`.
 Download and compile Ruby:
-``bash
+```bash
 mkdir /tmp/ruby && cd /tmp/ruby
 curl --remote-name --progress https://cache.ruby-lang.org/pub/ruby/2.3/ruby-2.3.1.tar.gz
 echo 'c39b4001f7acb4e334cb60a0f4df72d434bef711  ruby-2.3.1.tar.gz' | shasum --check - && tar xzf ruby-2.3.1.tar.gz
@@ -36,13 +36,13 @@ cd ruby-2.3.1
 ./configure --disable-install-rdoc
 make
 sudo make install
-``
+```
 Install Bundler:
-``bash
+```bash
 sudo gem install bundler --no-ri --no-rdoc
-``
+```
 ### 4. Get latest code