commands: Add "hugo build" as an alias for "hugo"

Closes #11391

testscripts/commands/gen.txt

@@ -1,6 +1,6 @@
 # Test the gen commands.
 # Note that adding new commands will require updating the NUM_COMMANDS value.
-env NUM_COMMANDS=43
+env NUM_COMMANDS=44
 
 hugo gen -h
 stdout 'A collection of several useful generators\.'

testscripts/commands/hugo_build.txt

@@ -0,0 +1,20 @@
+# Test the hugo build command (alias for hugo)
+
+hugo build
+stdout 'Pages.*|1'
+stdout 'Total in'
+checkfile public/index.html
+checkfile public/p1/index.html
+grep 'IsServer: false;IsProduction: true'  public/index.html
+
+-- hugo.toml --
+baseURL = "http://example.org/"
+disableKinds = ["RSS", "sitemap", "robotsTXT", "404", "taxonomy", "term"]
+-- layouts/index.html --
+Home|IsServer: {{ hugo.IsServer }};IsProduction: {{ hugo.IsProduction }}|
+-- layouts/_default/single.html --
+Title: {{ .Title }}
+-- content/p1.md --
+---
+title: "P1"
+---