Adjust color schemes slightly

- Make Perl6 a distinct blue (using Camelia’s wing as an aide)
- VCL is part of the Perl group
- Brighten Slim a bit so it does not conflict with Ada

lib/linguist/languages.yml

@@ -2349,7 +2349,7 @@ Perl:
 
 Perl6:
   type: programming
-  color: "#0298c3"
+  color: "#0000fb"
   extensions:
   - .6pl
   - .6pm
@@ -2967,7 +2967,7 @@ Slash:
 Slim:
   group: HTML
   type: markup
-  color: "#ff8877"
+  color: "#ff8f77"
   extensions:
   - .slim
   ace_mode: text
@@ -3209,8 +3209,8 @@ UnrealScript:
   ace_mode: java
 
 VCL:
+  group: Perl
   type: programming
-  color: "#0298c3"
   extensions:
   - .vcl
   tm_scope: source.varnish.vcl
@@ -3248,7 +3248,7 @@ Verilog:
 
 VimL:
   type: programming
-  color: "#199c4b"
+  color: "#199f4b"
   search_term: vim
   aliases:
   - vim