chore: Extract languages from zed crate (#8270)

- Moves languages module from `zed` into a separate crate. That way we
have less of a long pole at the end of compilation.
- Removes moot dependencies on editor/picker. This is totally harmless
and might help in the future if we decide to decouple picker from
editor.

Before:
```
Number of crates that depend on 'picker' but not on 'editor': 1
Total number of crates that depend on 'picker': 13
Total number of crates that depend on 'editor': 30
```
After:
```
Number of crates that depend on 'picker' but not on 'editor': 5
Total number of crates that depend on 'picker': 12
Total number of crates that depend on 'editor': 26
```
The more crates depend on just picker but not editor, the better in that
case.

Release Notes:

- N/A

crates/languages/src/cpp/highlights.scm

@@ -0,0 +1,158 @@
+(identifier) @variable
+
+(call_expression
+  function: (qualified_identifier
+    name: (identifier) @function))
+
+(call_expression
+  function: (identifier) @function)
+
+(call_expression
+  function: (field_expression
+    field: (field_identifier) @function))
+
+(preproc_function_def
+  name: (identifier) @function.special)
+
+(template_function
+  name: (identifier) @function)
+
+(template_method
+  name: (field_identifier) @function)
+
+(function_declarator
+  declarator: (identifier) @function)
+
+(function_declarator
+  declarator: (qualified_identifier
+    name: (identifier) @function))
+
+(function_declarator
+  declarator: (field_identifier) @function)
+
+((namespace_identifier) @type
+ (#match? @type "^[A-Z]"))
+
+(auto) @type
+(type_identifier) @type
+
+((identifier) @constant
+ (#match? @constant "^_*[A-Z][A-Z\\d_]*$"))
+
+(field_identifier) @property
+(statement_identifier) @label
+(this) @variable.special
+
+[
+  "break"
+  "case"
+  "catch"
+  "class"
+  "co_await"
+  "co_return"
+  "co_yield"
+  "const"
+  "constexpr"
+  "continue"
+  "default"
+  "delete"
+  "do"
+  "else"
+  "enum"
+  "explicit"
+  "extern"
+  "final"
+  "for"
+  "friend"
+  "if"
+  "if"
+  "inline"
+  "mutable"
+  "namespace"
+  "new"
+  "noexcept"
+  "override"
+  "private"
+  "protected"
+  "public"
+  "return"
+  "sizeof"
+  "static"
+  "struct"
+  "switch"
+  "template"
+  "throw"
+  "try"
+  "typedef"
+  "typename"
+  "union"
+  "using"
+  "virtual"
+  "volatile"
+  "while"
+  (primitive_type)
+  (type_qualifier)
+] @keyword
+
+[
+  "#define"
+  "#elif"
+  "#else"
+  "#endif"
+  "#if"
+  "#ifdef"
+  "#ifndef"
+  "#include"
+  (preproc_directive)
+] @keyword
+
+(comment) @comment
+
+[
+  (true)
+  (false)
+  (null)
+  (nullptr)
+] @constant
+
+(number_literal) @number
+
+[
+  (string_literal)
+  (system_lib_string)
+  (char_literal)
+  (raw_string_literal)
+] @string
+
+[
+  "."
+  ";"
+] @punctuation.delimiter
+
+[
+  "{"
+  "}"
+  "("
+  ")"
+  "["
+  "]"
+] @punctuation.bracket
+
+[
+  "--"
+  "-"
+  "-="
+  "->"
+  "="
+  "!="
+  "*"
+  "&"
+  "&&"
+  "+"
+  "++"
+  "+="
+  "<"
+  "=="
+  ">"
+  "||"
+] @operator