Docs: updates for file-based menu (#28500)

* initial

* cleanup

* remove bad aliases

* cleanup, fix links

* add docs-file-based-command

* update docs

* update readme

* fix broken links

* fix spelling

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

docs/sources/variables/syntax.md

@@ -1,11 +1,7 @@
 +++
 title = "Variables syntax and types"
 keywords = ["grafana", "templating", "documentation", "guide", "template", "variable"]
-type = "docs"
 aliases = ["/docs/grafana/latest/reference/templating"]
-[menu.docs]
-identifier = "variables-syntax-types"
-parent = "variables"
 weight = 100
 +++
 
@@ -16,9 +12,9 @@ Panel titles and metric queries can refer to variables using two different synta
 - `$varname`
   This syntax is easy to read, but it does not allow you to use a variable in the middle of a word.
   **Example:** apps.frontend.$server.requests.count
-- `${var_name}` Use this syntax when you want to interpolate a variable in the middle of an expression. 
+- `${var_name}` Use this syntax when you want to interpolate a variable in the middle of an expression.
 - `${var_name:<format>}` This format gives you more control over how Grafana interpolates values. Refer to [Advanced variable format options]({{< relref "advanced-variable-format-options.md" >}}) for more detail on all the formatting types.
-- `[[varname]]` Do not use. Deprecated old syntax, will be removed in a future release. 
+- `[[varname]]` Do not use. Deprecated old syntax, will be removed in a future release.
 
 Before queries are sent to your data source the query is _interpolated_, meaning the variable is replaced with its current value. During
 interpolation, the variable value might be _escaped_ in order to conform to the syntax of the query language and where it is used.