doc & skpkg: move doc/manual to docs/ and update pre-commit config file

.codespell/ignore_words.txt

@@ -6,3 +6,9 @@ mater
 
 ;; Frobenius norm used in np.linalg.norm
 fro
+
+;; variable name for a pair type multiplicity in BaseDebyeSum.cpp
+multipl
+
+;; custom scattering factor label used in TestScatteringFactorTable.hpp
+ccustom

.gitattributes

@@ -1,4 +1,4 @@
 /.gitattributes  export-ignore
 /.gitignore  export-ignore
-/doc  export-ignore
+/docs  export-ignore
 gitarchive.cfg  export-subst

.github/workflows/check-news-item.yml

@@ -3,7 +3,7 @@ name: Check for News
 on:
   pull_request_target:
     branches:
-      - main  # GitHub does not evaluate expressions in trigger filters; edit this value if your base branch is not main
+      - main # GitHub does not evaluate expressions in trigger filters; edit this value if your base branch is not main
 
 jobs:
   check-news-item:

.pre-commit-config.yaml

@@ -9,6 +9,12 @@ ci:
   autoupdate_schedule: monthly
   skip: [no-commit-to-branch]
   submodules: false
+# Leave the vendored CxxTest SCons tool and the data tables untouched.
+exclude: |
+  (?x)^(
+    site_scons/site_tools/cxxtest\.py|
+    .*\.(cif|dat)
+  )$
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v6.0.0