Hard-wrap CONTRIBUTING-DOCUMENTATION at 90 chars

CONTRIBUTING-DOCUMENTATION.adoc

@@ -1,42 +1,51 @@
 = How to contribute to the reference
 
-The Spring Framework reference now uses http://asciidoctor.org/[asciidoctor]. This document describes how to contribute documentation updates.
+The Spring Framework reference now uses http://asciidoctor.org/[asciidoctor]. This
+document describes how to contribute documentation updates.
 
 == Building with Gradle
 
-You can build the documentation using gradle using the `reference` task. For example, from the project root execute the following command:
+You can build the documentation using gradle using the `reference` task. For example, from
+the project root execute the following command:
 
-  ./gradlew reference
+	./gradlew reference
 
 the output will be available at `spring-framework/build/reference/htmlsingle/index.html`
 
 == Live editing
 
 One of the nice features about using asciidoctor is the support for live editing.
 
-You will find a Guardfile already present at `spring-framework/src/asciidoc/Guardfile`. Make sure first to follow
-the setup instructions within the http://asciidoctor.org/docs/editing-asciidoc-with-live-preview/[Editing AsciiDoc with Live Preview]
-document. Once you have done that, there are additional gems to install to make it work (assuming that you are using
-http://livereload.com/[LiveReload]):
+You will find a Guardfile already present at `spring-framework/src/asciidoc/Guardfile`.
+Make sure first to follow the setup instructions within the
+http://asciidoctor.org/docs/editing-asciidoc-with-live-preview/[Editing AsciiDoc with Live Preview]
+document. Once you have done that, there are additional gems to install to make it work
+(assuming that you are using http://livereload.com/[LiveReload]):
 
-  gem install guard-rspec guard-livereload
+	gem install guard-rspec guard-livereload
 
-When running `guard start` within the `src/asciidoc/` folder, any changes to the `src/asciidoc/index.adoc` file will automatically be written at `src/asciidoc/build/index.html`.
+When running `guard start` within the `src/asciidoc/` folder, any changes to the
+`src/asciidoc/index.adoc` file will automatically be written at
+`src/asciidoc/build/index.html`.
 
 == Troubleshooting
 
-* If you are using LiveReload, make sure to select _Allow access to file URLs_ in the LiveEdit plugin options of
-  your browser.
-* The icon used to enable _LiveReload_ can be a bit confusing. The dot is empty when it is disabled and full when
-  the plugin is active. Make sure to enable it on the tab displaying the `index.html` file.
-* Ensure you are _not_ running guard start at all as two instances could not run at the same time. To exit a current
-  session in a clean way, just type e in the shell.
+* If you are using LiveReload, make sure to select _Allow access to file URLs_ in the
+  LiveEdit plugin options of your browser.
+* The icon used to enable _LiveReload_ can be a bit confusing. The dot is empty when it is
+  disabled and full when the plugin is active. Make sure to enable it on the tab
+  displaying the `index.html` file.
+* Ensure you are _not_ running guard start at all as two instances could not run at the
+  same time. To exit a current session in a clean way, just type e in the shell.
 
 == Documentation notes
 
 Some notes on documentation
 
-* It is important to keep whitespaces to a minimum to make it simple to edit files. This means use an editor with line wrapping rather than manually inserting hard returns.
+* Documentation is wrapped at 90 chars, ensure that you manually wrap your edits
+* Tabs are used for indentation, do not use spaces
+* Follow the existing style when inserting `source` blocks
 * http://asciidoctor.org/docs/asciidoc-syntax-quick-reference/[Asciidoctor Quick Reference]
 * http://asciidoctor.org/docs/user-manual/[Asciidoctor Manual]
 * http://asciidoctor.org/docs/asciidoc-writers-guide/[Asciidoctor Writers Guide]
+