ci: Sort jobs and names in a better way

Instead of:

```
CI / Check coding style
CI / Check spelling
CI / debian | Autotools | unit | signal
CI / debian | Meson | unit+func | libomemo
CI / debian | Meson | unit+func | signal
CI / fedora | Autotools | unit | signal
CI / ubuntu | Autotools | unit | signal
Cygwin / cygwin-build
```

We will sort them into "Style", "Linux" and "Cygwin".

.github/workflows/cygwin-build.yml

@@ -8,6 +8,7 @@ on:
 
 jobs:
   cygwin-build:
+    name: build only
     runs-on: windows-latest
     env:
       CYGWIN: winsymlinks:nativestrict

.github/workflows/main.yml

@@ -1,4 +1,4 @@
-name: CI
+name: Linux
 
 on:
   push:
@@ -18,28 +18,28 @@ jobs:
       matrix:
         include:
           - flavor: debian
-            buildsystem: Autotools
+            buildsystem: autotools
             tests: unit
             omemo: signal
             script: ./ci/ci-build.sh
           - flavor: fedora
-            buildsystem: Autotools
+            buildsystem: autotools
             tests: unit
             omemo: signal
             script: ./ci/ci-build.sh
           - flavor: ubuntu
-            buildsystem: Autotools
+            buildsystem: autotools
             tests: unit
             omemo: signal
             script: ./ci/ci-build.sh
           - flavor: debian
-            buildsystem: Meson
+            buildsystem: meson
             tests: unit+func
             omemo: signal
             script: ./ci/ci-meson-build.sh
             omemo_env: libsignal
           - flavor: debian
-            buildsystem: Meson
+            buildsystem: meson
             tests: unit+func
             omemo: libomemo
             script: ./ci/ci-meson-build.sh
@@ -54,36 +54,3 @@ jobs:
         run: |
           docker build -f ci/Dockerfile.${{ matrix.flavor }} -t profanity .
           docker run ${OMEMO_BACKEND:+ -e OMEMO_BACKEND} profanity ${{ matrix.script }}
-
-  code-style:
-    runs-on: ubuntu-22.04
-    name: Check coding style
-    continue-on-error: true
-    steps:
-      - uses: actions/checkout@v2
-      # if this check fails, you have to update the number of auto types known and the list of auto types in the check below
-      - name: Check auto types are up-to-date
-        run: |
-          [[ "$(find src -type f -name '*.[ch]' -exec awk '/^#define auto_[\W]*/ {print $2}' '{}' \; | sort -u | wc -l)" == "9" ]] || exit -1
-      - name: Check auto types are initialized
-        run: |
-          grep -P 'auto_(char|gchar|gcharv|gerror|guchar|jid|sqlite|gfd|FILE)[\w *]*;$' -r src && exit -1 || true
-      - name: Run clang-format
-        uses: jidicula/clang-format-action@v4.16.0
-        with:
-          clang-format-version: '21'
-          check-path: 'src'
-
-  spell-check:
-    runs-on: ubuntu-22.04
-    name: Check spelling
-    continue-on-error: true
-    steps:
-      - uses: actions/checkout@v2
-      - name: install dependencies
-        run: |
-          sudo apt update
-          sudo apt install -y --no-install-recommends codespell
-      - name: Check spelling
-        run: |
-          codespell

.github/workflows/style.yml

@@ -0,0 +1,45 @@
+name: Style
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  code-style:
+    runs-on: ubuntu-22.04
+    name: coding style
+    continue-on-error: true
+    steps:
+      - uses: actions/checkout@v2
+      # if this check fails, you have to update the number of auto types known and the list of auto types in the check below
+      - name: Check auto types are up-to-date
+        run: |
+          [[ "$(find src -type f -name '*.[ch]' -exec awk '/^#define auto_[\W]*/ {print $2}' '{}' \; | sort -u | wc -l)" == "9" ]] || exit -1
+      - name: Check auto types are initialized
+        run: |
+          grep -P 'auto_(char|gchar|gcharv|gerror|guchar|jid|sqlite|gfd|FILE)[\w *]*;$' -r src && exit -1 || true
+      - name: Run clang-format
+        uses: jidicula/clang-format-action@v4.16.0
+        with:
+          clang-format-version: '21'
+          check-path: 'src'
+
+  spell-check:
+    runs-on: ubuntu-22.04
+    name: spellcheck
+    continue-on-error: true
+    steps:
+      - uses: actions/checkout@v2
+      - name: install dependencies
+        run: |
+          sudo apt update
+          sudo apt install -y --no-install-recommends codespell
+      - name: Check spelling
+        run: |
+          codespell