CI: Remove explanatory comments about pnpm cache in workflows

Author: ndbroadbent

.github/workflows/deploy-site.yml

@@ -47,8 +47,6 @@ jobs:
         with:
           version: latest
 
-      # Rely on actions/setup-node pnpm cache; no manual pnpm store cache needed
-
       - name: Install site dependencies
         run: |
           cd site && pnpm install --frozen-lockfile

.github/workflows/test.yml

@@ -35,8 +35,6 @@ jobs:
         with:
           version: latest
 
-      # Using actions/setup-node pnpm cache; no manual pnpm store cache
-
       - name: Install npm packages
         run: |
           # Install root and site pnpm dependencies
@@ -107,8 +105,6 @@ jobs:
         with:
           version: latest
 
-      # Using actions/setup-node pnpm cache; no manual pnpm store cache
-
       - name: Install site dependencies
         run: cd site && pnpm install --frozen-lockfile