Arrange languages alphabetically

+ Keep Raku alphabetically in README.md
+ `raku` is the executable now since Raku version 2019.11 release, We
  already have v2020.05.2 release, so command is `raku`, reflect that

+ Add Raku in keywords in package.json

Author: sumanstats

README.md

@@ -79,7 +79,6 @@ Currently supported grammars are:
 | [Pandoc] Markdown                   | Yes        |                 | [language-pfm]                | [`panzer`]                |                                                                                                                                                                                                                                                                 |
 | [Pascal]                            | Yes        | Yes             | [language-pascal]             | `fpc`                     |                                                                                                                                                                                                                                                                 |
 | [Perl]                                | Yes        | Yes             |                               |                           |                                                                                                                                                                                                                                                                 |
-| [Raku]                            | Yes        | Yes             |                               | `raku` or `perl6`                   |                                                                                                                                                                                                                                                                 |
 | PHP                                 | Yes        | Yes             |                               |                           |                                                                                                                                                                                                                                                                 |
 | [PostgreSQL]                        | Yes        | Yes             | [language-pgsql]              | [`psql`]                  | Connects as user `PGUSER` to database `PGDATABASE`. Both default to your operating system's `USERNAME`, but can be set in the process environment or in Atom's [`init` file]: `process.env.PGUSER = {user name}` and `process.env.PGDATABASE = {database name}` |
 | [POV-Ray]                           | Yes        |                 | [atom-language-povray]        | `povengine`/`povray`      |                                                                                                                                                                                                                                                                 |
@@ -90,6 +89,7 @@ Currently supported grammars are:
 | Python                              | Yes        | Yes             |                               |                           |                                                                                                                                                                                                                                                                 |
 | [R]                                 | Yes        | Yes             | [language-r]                  | `Rscript`                 |                                                                                                                                                                                                                                                                 |
 | [Racket]                            | Yes        | Yes             | [language-racket]             | `racket`                  |                                                                                                                                                                                                                                                                 |
+| [Raku]                              | Yes        | Yes             |                               | `raku`                    |                                                                                                                                                                                                                                                                 |
 | [Reason]                            | Yes        | Yes             | [language-reason]             | `rebuild`                 |                                                                                                                                                                                                                                                                 |
 | [Ren'Py]                            | Yes        | No              | [language-renpy]              | `renpy`                   | Runs your project at the root of the current file.                                                                                                                                                                                                              |
 | [Robot Framework]                   | Yes        | No              | [language-robot-framework]    | `robot`                   | The output location depends on the `CWD` behaviour which can be altered in settings.                                                                                                                                                                            |

lib/grammars/perl.coffee

@@ -21,4 +21,4 @@ exports['Raku'] =
     command: 'raku'
     args: ({filepath}) -> [filepath]
 
-exports['Raku/Perl 6'] = exports['Raku']
+exports['Perl 6'] = exports['Raku']

package.json

@@ -97,6 +97,7 @@
     "PHP",
     "PowerShell",
     "Python",
+    "Raku",
     "RSpec",
     "Ruby",
     "Ruby on Rails",