common/hugo: Add hugo.IsServer and hugo.IsDevelopment

And deprecate site.IsServer.

Closes #11510

content/en/functions/hugo.md

@@ -31,11 +31,17 @@ relatedfuncs: []
 `hugo.GoVersion`
 : (`string`) The Go version used to compile the Hugo binary (e.g., `go1.20.4`). {{< new-in "0.101.0" >}}
 
+`hugo.IsDevelopment`
+: (`bool`) Returns `true` if `hugo.Environment` is "development".
+
 `hugo.IsExtended`
 : (`bool`) Returns `true` if the Hugo binary is the extended version.
 
 `hugo.IsProduction`
-: (`bool`) Returns `true` if `hugo.Environment` is set to the production environment.
+: (`bool`) Returns `true` if `hugo.Environment` is "production".
+
+`hugo.IsServer`
+: (`bool`) Returns `true` if the site is being served with Hugo's built-in server.
 
 `hugo.Version`
 : (`hugo.VersionString`) The current version of the Hugo binary (e.g., `0.112.1`).

content/en/variables/site.md

@@ -47,9 +47,6 @@ All the methods below, e.g. `.Site.RegularPages` can also be reached via the glo
 .Site.IsMultiLingual
 : whether there are more than one language in this site. See [Multilingual](/content-management/multilingual/) for more information.
 
-.Site.IsServer
-: a boolean to indicate if the site is being served with Hugo's built-in server. See [`hugo server`](/commands/hugo_server/) for more information.
-
 .Site.Language.Lang
 : the language code of the current locale (e.g., `en`).