Lint config.example.yml and config.cr

Follow lint indications :
- https://github.com/iv-org/invidious/pull/2915#discussion_r812396203
- https://github.com/iv-org/invidious/pull/2915#discussion_r812396807

config/config.example.yml

@@ -315,12 +315,13 @@ https_only: false
 channel_threads: 1
 
 ##
-## Time between two jobs for crawling videos from channels
+## Time interval between two executions of the job that crawls
+## channel videos (subscriptions update).
 ##
-## Accepted values: a valid time interval (like 1h30m or 90min)
+## Accepted values: a valid time interval (like 1h30m or 90m)
 ## Default: 30m
 ##
-channel_refresh_interval: 30min
+#channel_refresh_interval: 30m
 
 ##
 ## Forcefully dump and re-download the entire list of uploaded

src/invidious/config.cr

@@ -58,7 +58,7 @@ class Config
 
   # Number of threads to use for crawling videos from channels (for updating subscriptions)
   property channel_threads : Int32 = 1
-  # Time between two jobs for crawling videos from channels
+  # Time interval between two executions of the job that crawls channel videos (subscriptions update).
   @[YAML::Field(converter: Preferences::TimeSpanConverter)]
   property channel_refresh_interval : Time::Span = 30.minutes
   # Number of threads to use for updating feeds