More administrivia

Go over precommit configuration
Remove anachronistic python3 -> python
Note 3.10 category in packaging

Author: rocky

.pre-commit-config.yaml

@@ -1,16 +1,22 @@
+default_language_version:
+  python: python
 repos:
 -   repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.0.1
     hooks:
+    - id: check-merge-conflict
     - id: check-yaml
     - id: debug-statements
+      stages: [commit]
     - id: end-of-file-fixer
+      stages: [commit]
     - id: trailing-whitespace
     - id: check-json
       exclude: mathics_scanner/data/characters.json
 -   repo: https://github.com/psf/black
     rev: 22.3.0
     hooks:
     - id: black
-      language_version: python3
+      language_version: python
+      stages: [commit]
       exclude: version.py

Makefile

@@ -5,7 +5,7 @@
 # remake --tasks to shows the targets and the comments
 
 GIT2CL ?= admin-tools/git2cl
-PYTHON ?= python3
+PYTHON ?= python
 PIP ?= pip3
 RM  ?= rm
 

setup.py

@@ -117,6 +117,7 @@ def subdirs(root, file="*.*", depth=10):
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: Implementation :: CPython",
         "Programming Language :: Python :: Implementation :: PyPy",
         "Topic :: Scientific/Engineering",