Add module to map nerd font symbol names to codepoints

I generated nerdfonts_data.rs with this shell script; it uses `i_all.sh`
from the nerdfonts repo to get the base mapping:

```
source ./lib/i_all.sh

echo "//! Data mapping nerd font symbol names to their char codepoints"
echo "pub const NERD_FONT_GLYPHS: &[(&str, char)] = &["
for var in "${!i@}"; do
  # trim 'i_' prefix
  glyph_name=${var#*_}
  glyph_char=${!var}
  glyph_code=$(printf "%x" "'$glyph_char'")
  echo "(\"$glyph_name\", '\u{$glyph_code}'), // $glyph_char"
done
echo "];"
```

Then intent is to use it in wezterm:

```
local wezterm = require 'wezterm'

wezterm.log_info(wezterm.nerdfonts.dev_mozilla)
```

config/src/lua.rs

@@ -101,6 +101,7 @@ pub fn make_lua_context(config_file: &Path) -> anyhow::Result<Lua> {
 
         wezterm_mod.set("target_triple", crate::wezterm_target_triple())?;
         wezterm_mod.set("version", crate::wezterm_version())?;
+        wezterm_mod.set("nerdfonts", NerdFonts{})?;
         wezterm_mod.set("home_dir", crate::HOME_DIR.to_str())?;
         wezterm_mod.set(
             "running_under_wsl",
@@ -1028,3 +1029,13 @@ pub fn truncate_right(s: &str, max_width: usize) -> String {
     }
     result
 }
+
+struct NerdFonts {}
+
+impl mlua::UserData for NerdFonts {
+    fn add_methods<'lua, M: mlua::UserDataMethods<'lua, Self>>(methods: &mut M) {
+        methods.add_meta_method(mlua::MetaMethod::Index, |_, _, key: String| -> mlua::Result<Option<String>> {
+            Ok(termwiz::nerdfonts::NERD_FONTS.get(key.as_str()).map(|c| c.to_string()))
+        });
+    }
+}

termwiz/src/lib.rs

@@ -57,6 +57,8 @@ pub mod istty;
 pub mod keymap;
 pub mod lineedit;
 mod macros;
+pub mod nerdfonts;
+mod nerdfonts_data;
 mod readbuf;
 pub mod render;
 pub mod surface;

termwiz/src/nerdfonts.rs

@@ -0,0 +1,12 @@
+use std::collections::HashMap;
+
+lazy_static::lazy_static! {
+    pub static ref NERD_FONTS: HashMap<&'static str, char> = build_map();
+}
+
+fn build_map() -> HashMap<&'static str, char> {
+    crate::nerdfonts_data::NERD_FONT_GLYPHS
+        .iter()
+        .map(|tuple| *tuple)
+        .collect()
+}