Extend Ruby word characters to include valid identifier chars (#7824)

In Ruby `_$=@!:?` can all be part of an identifier. If we don't have
them in this list, autocomplete doesn't work as expected.

See: https://gist.github.com/misfo/1072693

This fixes one part of #7819 but not the whole ticket.

Release Notes:

- Fixed completions in Ruby not working for identifiers that start or
end with special characters (e.g.: `@`)

crates/zed/src/languages/ruby/config.toml

@@ -18,7 +18,7 @@ path_suffixes = [
     "rdoc",
     "thor",
     "pryrc",
-  "simplecov"
+    "simplecov",
 ]
 first_line_pattern = '^#!.*\bruby\b'
 line_comments = ["# "]
@@ -27,7 +27,14 @@ brackets = [
     { start = "{", end = "}", close = true, newline = true },
     { start = "[", end = "]", close = true, newline = true },
     { start = "(", end = ")", close = true, newline = true },
-  { start = "\"", end = "\"", close = true, newline = false, not_in = ["comment", "string"] },
-  { start = "'", end = "'", close = true, newline = false, not_in = ["comment", "string"] },
+    { start = "\"", end = "\"", close = true, newline = false, not_in = [
+        "comment",
+        "string",
+    ] },
+    { start = "'", end = "'", close = true, newline = false, not_in = [
+        "comment",
+        "string",
+    ] },
 ]
 collapsed_placeholder = "# ..."
+word_characters = ["_", "$", "=", "@", "!", ":", "?"]