.pre-commit-config.yaml: remove workarounds, add merge conflict & line-ending checks

.pre-commit-config.yaml

@@ -4,11 +4,6 @@ ci:
   # https://github.com/pre-commit-ci/issues/issues/83
   autoupdate_schedule: quarterly
 
-# Aminda has too bleeding edge Python, pypy3 should be universal enough to
-# work for everyone.
-default_language_version:
-  python: pypy3
-
 repos:
   - repo: https://github.com/thlorenz/doctoc
     rev: v2.2.0
@@ -29,7 +24,10 @@ repos:
       - id: end-of-file-fixer
       - id: fix-byte-order-marker
       - id: trailing-whitespace
-        exclude_types: [tsv, markdown]
+        args: ["--markdown-linebreak-ext", "md,markdown"]
+        exclude_types: [svg, tsv]
+      - id: check-merge-conflict
+      - id: mixed-line-ending
 
   - repo: https://github.com/pre-commit/mirrors-prettier
     rev: "v3.0.3"