[ci]: check for typos via codespell (#326)

also fix any found issues.

Reviewed-on: https://codeberg.org/nsxiv/nsxiv/pulls/326
Reviewed-by: Berke Kocaoğlu <berke.kocaoglu@metu.edu.tr>

.woodpecker/spell.yml

@@ -0,0 +1,11 @@
+branches: master
+
+# NOTE: codespell not available on stable alpine, use edge
+pipeline:
+  spell-check:
+    image: alpine:edge
+    commands: |
+      apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing py3-codespell >/dev/null
+      find . \( -name '*.patch' -o -name '*.diff' -o -name '*.md' \) -print | \
+        xargs -I{} codespell {}
+      codespell nsxiv.1 config.mk Makefile