Include the lexer mapping for pygments

Author: pradyunsg

pyproject.toml

@@ -39,6 +39,7 @@ substitute = [
   # pkg_resource's vendored packages are directly vendored in pip.
   { match='pkg_resources\.extern', replace="pip._vendor" },
   { match='from \.extern', replace="from pip._vendor" },
+  { match='''\('pygments\.lexers\.''', replace="('pip._vendor.pygments.lexer." },
 ]
 drop = [
   # contains unnecessary scripts
@@ -52,7 +53,7 @@ drop = [
   "pkg_resources/extern/",
   # trim vendored pygments styles and lexers
   "pygments/styles/[!_]*.py",
-  '^pygments/lexers/(?!python|__init__).*\.py$',
+  '^pygments/lexers/(?!python|__init__|_mapping).*\.py$',
   # trim rich's markdown support
   "rich/markdown.py",
 ]