Add JSON5 support for languages.json (#986)

Cargo.lock

@@ -608,6 +608,17 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "json5"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96b0db21af676c1ce64250b5f40f3ce2cf27e4e47cb91ed91eb6fe9350b430c1"
+dependencies = [
+ "pest",
+ "pest_derive",
+ "serde",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -1338,6 +1349,7 @@ dependencies = [
  "grep-searcher",
  "hex",
  "ignore",
+ "json5",
  "log",
  "num-format",
  "once_cell",

Cargo.toml

@@ -35,6 +35,7 @@ panic = "abort"
 tera = "1.15"
 ignore = "0.4"
 serde_json = "1"
+json5 = "0.4"
 
 [dependencies]
 aho-corasick = "0.7"

build.rs

@@ -1,8 +1,9 @@
 extern crate ignore;
 extern crate serde_json;
+extern crate json5;
 
 use std::ffi::OsStr;
-use std::fs::{self, File};
+use std::fs;
 use std::path::Path;
 use std::{cmp, env, error};
 
@@ -20,7 +21,8 @@ fn main() -> Result<(), Box<dyn error::Error>> {
 fn generate_languages(out_dir: &OsStr) -> Result<(), Box<dyn error::Error>> {
     let mut tera = tera::Tera::default();
 
-    let mut json: Value = serde_json::from_reader(File::open(&"languages.json")?)?;
+    let json_string: String = fs::read_to_string("languages.json")?.parse()?;
+    let mut json: Value = json5::from_str(&json_string)?;
 
     for (_key, ref mut item) in json
         .get_mut("languages")