Unify racer code completion format

Makes all the suggestions on the completion menu have the same format:
  {type}{suggestedWord}{extra description}

the type column is aligned to 6 characters wide (and aligned to the right),
to allow the suggestion to be easily visually detectable and, as a bonus,
the type too.

For example, a bit of menu would look like this:
        fn stdout() -> Stdout
     trait BufRead: Read
    struct BufReader<R>

Type is one of the following:
  -     fn
  -   enum
  -    mod
  -  trait
  - struct

It also trims the module extra bits to only 30 characters long (it can be a lot longer than that)

1 files changed, 30 insertions, 3 deletions

diff --git a/rc/extra/racer.kak b/rc/extra/racer.kak
index 20f6c367..06bed711 100644
--- a/rc/extra/racer.kak
+++ b/rc/extra/racer.kak
@@ -29,13 +29,40 @@ define-command racer-complete -docstring "Complete the current selection with ra
                     gsub(/\|/, "\\|", menu)
                     if (type == "Function") {
                         sub(word, "{default+e}" word "{default+d}", menu)
+                        gsub(/^fn /, "    fn ", menu)                            # The extra spaces are there to vertically align
+                                                                                 # the type of element on the menu to make it easy
+                                                                                 # to read
                         menu = "{default+d}" menu
-                        word = word "("
                     } else if (type == "Enum") {
                         menu = substr(menu, 0, length(menu) - 2)
                         sub(word, "{default+e}" word "{default+d}", menu)
-                        menu = "{default+d}" menu
-                        word = word "::"
+                        gsub(/^enum /, "  enum ", menu)                          # The extra spaces are there to vertically align
+                                                                                 # the type of element on the menu to make it easy
+                                                                                 # to read
+                    } else if (type == "Module") {
+                        if (length(menu) > 30) {                                 # The "menu" bit (as returned by racer),
+                                                                                 # contains the path to the source file
+                                                                                 # containing the module...
+
+                          menu = substr(menu, length(menu) - 29, 30)             # ... trimming it, so the completion menu
+                                                                                 # doesn''t get distorted if it''s too long
+                        }
+                        menu = "   mod {default+e}" word "{default+d}   .." menu # The extra spaces are there to vertically align
+                                                                                 # the type of element on the menu to make it easy
+                                                                                 # to read
+                    } else if (type == "Trait") {
+                        sub(word, "{default+e}" word "{default+d}", menu)
+                        gsub(/^trait /, " trait ", menu)                         # The extra spaces are there to vertically align
+                                                                                 # the type of element on the menu to make it easy
+                                                                                 # to read
+                    } else if (type == "Type") {
+                        sub(word, "{default+e}" word "{default+d}", menu)
+                        gsub(/^type /, "  type ", menu)                          # The extra spaces are there to vertically align
+                                                                                 # the type of element on the menu to make it easy
+                                                                                 # to read
+                    } else if (type == "Struct") {
+                        sub(word, "{default+e}" word "{default+d}", menu)        # Struct doesn''t have extra spaces because it''s
+                                                                                 # the longest keyword
                     } else {
                         menu = "{default+e}" word "{default+d} " menu
                     }