fix: improve metrics display clarity on Introduction page

- Fix spacing in "Active Slack Users" title (was "ActiveSlack Users")
- Add "Total" prefix to Pull Requests and Issues metrics for clarity
- Addresses issues identified in #59 regarding unclear metric labeling

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Co-authored-by: Edmund Miller <edmundmiller@users.noreply.github.com>

Author: claude[bot]

pages/index.md

@@ -31,7 +31,7 @@ The numbers below track our growth over the various channels that the nf-core co
 <BigValue
   data={community_growth_slack_users}
   value=members
-  title="ActiveSlack Users"
+  title="Active Slack Users"
   sparkline=month
   link='/community/slack'
   minWidth=30%
@@ -78,15 +78,15 @@ Whilst we always prefer quality over quantity, these numbers reflect the work ou
 <BigValue
     data={code_growth_gh_prs}
     value=num_prs
-    title="Pull Requests"
+    title="Total Pull Requests"
     sparkline=month
     link="/code/pull_requests"
     minWidth=30%
 />
 <BigValue
     data={code_growth_gh_issues}
     value=num_issues
-    title="Issues"
+    title="Total Issues"
     sparkline=month
     fmt=num0
     minWidth=30%