Fix Markdown rendering of indented code blocks (#814)

... by using plain indented code blocks instead of indented fenced
code blocks.

While here also fix list rendering and add missing Go template escaping
in inline `values` map example.

Signed-off-by: Stoned Elipot <stoned.elipot@gmail.com>

docs/writing-helmfile.md

@@ -111,40 +111,41 @@ releases:
 ```
 
 Release Templating supports the following parts of release definition:
+
 - basic fields: `name`, `namespace`, `chart`, `version`
+
 - boolean fields: `installed`, `wait`, `waitForJobs`, `verify` by the means of additional text
   fields designed for templating only: `installedTemplate`, `waitTemplate`, `verifyTemplate`
-  ```yaml
+
         # ...
           installedTemplate: '{{`{{ eq .Release.Namespace "kube-system" }}`}}'
           waitTemplate: '{{`{{ eq .Release.Labels.tag "safe" | not }}`}}'
         # ...
-  ```
+
 - `set` block values:
-  ```yaml
+
         # ...
           setTemplate:
           - name: '{{`{{ .Release.Name }}`}}'
             values: '{{`{{ .Release.Namespace }}`}}'
         # ...
-  ```
+
 - `values` and `secrets` file paths:
-  ```yaml
+
         # ...
           valuesTemplate:
           - config/{{`{{ .Release.Name }}`}}/values.yaml
           secrets:
           - config/{{`{{ .Release.Name }}`}}/secrets.yaml
         # ...
-  ```
+
 - inline `values` map:
-  ```yaml
+
         # ...
           valuesTemplate:
           - image:
-        tag: `{{ .Release.Labels.tag }}`
+              tag: '{{`{{ .Release.Labels.tag }}`}}'
         # ...
-  ```
 
 Previously, we've been using YAML anchors for release template inheritance.
 It turned out not work well when you wanted to nest templates for complex use cases and/or you want a fine control over which fields to inherit or not.