Revert "Only show greeting on interactive login sessions"

This reverts commit 3d0ea5fe79.

share/functions/__fish_config_interactive.fish

@@ -303,6 +303,26 @@ function __fish_config_interactive -d "Initializations that should be performed
         set -g fish_pager_color_description yellow
         set -g fish_pager_color_progress cyan
 
+        # Don't allow setting color other than what linux offers (see #2001)
+        functions -e set_color
+        function set_color --shadow-builtin
+            set -l term_colors black red green yellow blue magenta cyan white normal
+            for a in $argv
+                if not contains -- $a $term_colors
+                    switch $a
+                        # Also allow options
+                        case "-*"
+                            continue
+                        case "*"
+                            echo "Color not valid in TERM = linux: $a"
+                            return 1
+                    end
+                end
+            end
+            builtin set_color $argv
+            return $status
+        end
+
         # Set fish_prompt to a VT-friendly version
         # without color or unicode
         function fish_prompt