tests/checks/read: add test for non-interactive use of commandline

tests/checks/commandline.fish

@@ -65,3 +65,10 @@ $fish -ic '
 # CHECK: hello
 # CHECK: helloworld
 # CHECK: hello world
+
+$fish -c 'commandline foo'
+# CHECKERR: commandline: Can not set commandline in non-interactive mode
+# CHECKERR: Standard input (line 1):
+# CHECKERR: commandline foo
+# CHECKERR: ^
+# CHECKERR: (Type 'help commandline' for related documentation)

tests/checks/read.fish

@@ -245,7 +245,7 @@ if test (string length "$x") -ne $fish_read_limit
     echo reading with a limited amount of input data failed the length test
 end
 
-# Confirm reading non-interactively works -- \#4206 regression
+# Confirm reading non-interactively works -- #4206 regression
 echo abc\ndef | $fish -i -c 'read a; read b; set --show a; set --show b'
 #CHECK: $a: set in global scope, unexported, with 1 elements
 #CHECK: $a[1]: |abc|