Fix #1799 by linking to Liquid docs (#1953)

app/models/agents/change_detector_agent.rb

@@ -5,7 +5,7 @@ module Agents
     description <<-MD
       The Change Detector Agent receives a stream of events and emits a new event when a property of the received event changes.
 
-      `property` specifies a Liquid template that expands to the property to be watched, where you can use a variable `last_property` for the last property value.  If you want to detect a new lowest price, try this: `{% assign drop = last_property | minus: price %}{% if last_property == blank or drop > 0 %}{{ price | default: last_property }}{% else %}{{ last_property }}{% endif %}`
+      `property` specifies a [Liquid](https://github.com/cantino/huginn/wiki/Formatting-Events-using-Liquid) template that expands to the property to be watched, where you can use a variable `last_property` for the last property value.  If you want to detect a new lowest price, try this: `{% assign drop = last_property | minus: price %}{% if last_property == blank or drop > 0 %}{{ price | default: last_property }}{% else %}{{ last_property }}{% endif %}`
 
       `expected_update_period_in_days` is used to determine if the Agent is working.
 

app/models/agents/commander_agent.rb

@@ -19,7 +19,7 @@ module Agents
 
       * `configure`: Target Agents have their options updated with the contents of `configure_options`.
 
-      Here's a tip: you can use Liquid templating to dynamically determine the action type.  For example:
+      Here's a tip: you can use [Liquid](https://github.com/cantino/huginn/wiki/Formatting-Events-using-Liquid) templating to dynamically determine the action type.  For example:
 
       - To create a CommanderAgent that receives an event from a WeatherAgent every morning to kick an agent flow that is only useful in a nice weather, try this: `{% if conditions contains 'Sunny' or conditions contains 'Cloudy' %}` `run{% endif %}`
 

app/models/agents/data_output_agent.rb

@@ -57,7 +57,7 @@ module Agents
 
         # Liquid Templating
 
-        In Liquid templating, the following variable is available:
+        In [Liquid](https://github.com/cantino/huginn/wiki/Formatting-Events-using-Liquid) templating, the following variable is available:
 
         * `events`: An array of events being output, sorted in the given order, up to `events_to_show` in number.  For example, if source events contain a site title in the `site_title` key, you can refer to it in `template.title` by putting `{{events.first.site_title}}`.
 

app/models/agents/email_agent.rb

@@ -9,7 +9,7 @@ module Agents
     description <<-MD
       The Email Agent sends any events it receives via email immediately.
 
-      You can specify the email's subject line by providing a `subject` option, which can contain Liquid formatting.  E.g.,
+      You can specify the email's subject line by providing a `subject` option, which can contain [Liquid](https://github.com/cantino/huginn/wiki/Formatting-Events-using-Liquid) formatting.  E.g.,
       you could provide `"Huginn email"` to set a simple subject, or `{{subject}}` to use the `subject` key from the incoming Event.
 
       By default, the email body will contain an optional `headline`, followed by a listing of the Events' keys.

app/models/agents/google_calendar_publish_agent.rb

@@ -32,7 +32,7 @@ module Agents
 
       `google` `service_account_email` - The authorised service account.
 
-      `google` `key_file` OR `google` `key` - The path to the key file or the key itself.  Liquid formatting is supported if you want to use a Credential.  (E.g., `{% credential google_key %}`)
+      `google` `key_file` OR `google` `key` - The path to the key file or the key itself.  [Liquid](https://github.com/cantino/huginn/wiki/Formatting-Events-using-Liquid) formatting is supported if you want to use a Credential.  (E.g., `{% credential google_key %}`)
 
       `google` `key_secret` - The secret for the key, typically 'notasecret'
 

app/models/agents/liquid_output_agent.rb

@@ -28,9 +28,7 @@ module Agents
 
         # Liquid Templating
 
-        The content you provide will be run as a Liquid template. The data from the last event received will be used when processing the Liquid template.
-
-        To learn more about Liquid templates, go here: [http://liquidmarkup.org](http://liquidmarkup.org "Liquid Templating")
+        The content you provide will be run as a [Liquid](https://github.com/cantino/huginn/wiki/Formatting-Events-using-Liquid) template. The data from the last event received will be used when processing the Liquid template.
 
         # Modes
 

app/models/agents/pushover_agent.rb

@@ -16,7 +16,7 @@ module Agents
       * `user`: the user or group key (not e-mail address).
       * `expected_receive_period_in_days`:  is maximum number of days that you would expect to pass between events being received by this agent.
 
-      The following options are all Liquid templates whose evaluated values will be posted to the Pushover API.  Only the `message` parameter is required, and if it is blank API call is omitted.
+      The following options are all [Liquid](https://github.com/cantino/huginn/wiki/Formatting-Events-using-Liquid) templates whose evaluated values will be posted to the Pushover API.  Only the `message` parameter is required, and if it is blank API call is omitted.
 
       Pushover API has a `512` Character Limit including `title`.  `message` will be truncated.
 

app/models/agents/website_agent.rb

@@ -23,8 +23,8 @@ module Agents
 
       The WebsiteAgent can also scrape based on incoming events.
 
-      * Set the `url_from_event` option to a Liquid template to generate the url to access based on the Event.  (To fetch the url in the Event's `url` key, for example, set `url_from_event` to `{{ url }}`.)
-      * Alternatively, set `data_from_event` to a Liquid template to use data directly without fetching any URL.  (For example, set it to `{{ html }}` to use HTML contained in the `html` key of the incoming Event.)
+      * Set the `url_from_event` option to a [Liquid](https://github.com/cantino/huginn/wiki/Formatting-Events-using-Liquid) template to generate the url to access based on the Event.  (To fetch the url in the Event's `url` key, for example, set `url_from_event` to `{{ url }}`.)
+      * Alternatively, set `data_from_event` to a [Liquid](https://github.com/cantino/huginn/wiki/Formatting-Events-using-Liquid) template to use data directly without fetching any URL.  (For example, set it to `{{ html }}` to use HTML contained in the `html` key of the incoming Event.)
       * If you specify `merge` for the `mode` option, Huginn will retain the old payload and update it with new values.
 
       # Supported Document Types
@@ -128,7 +128,7 @@ module Agents
 
       # Liquid Templating
 
-      In Liquid templating, the following variables are available:
+      In [Liquid](https://github.com/cantino/huginn/wiki/Formatting-Events-using-Liquid) templating, the following variables are available:
 
       * `_url_`: The URL specified to fetch the content from.  When parsing `data_from_event`, this is not set.