workflows: remove the custom windows only jobs

Restore the job matrix to run on linux, macos and windows.

Remove lines with extra whitespace.

Improve the documentation of the Eowyn workflow.

Remove the single quoting of the workflow names.

.github/workflows/eowyn.yml

@@ -1,5 +1,5 @@
-name: 'Eowyn'
-# Tests all exercises
+# Test that exercises work with the latest Zig compiler.
+name: Eowyn
 
 on:
   pull_request:
@@ -13,35 +13,20 @@ defaults:
     shell: bash
 
 jobs:
-  build-linux_mac:
+  build:
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest, windows-latest, macos-latest]
     runs-on: ${{ matrix.os }}
     timeout-minutes: 30
     steps:
       - name: Checkout
         uses: actions/checkout@v3
-        
+
       - name: Setup Zig
         uses: goto-bus-stop/setup-zig@v2
         with:
           version: master
-          
-      - name: Run Eowyn
-        run: patches/eowyn.sh
-        
-  build-windows:
-    runs-on: windows-latest
-    timeout-minutes: 30
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v3
-        
-      - name: Setup Zig
-        uses: goto-bus-stop/setup-zig@v2
-        with:
-          version: master
-          
+
       - name: Run Eowyn
         run: patches/eowyn.sh