docs: update some invalid documentation links (#983)

Update some documentation links (some were dead links)

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -4,7 +4,7 @@ body:
   - type: markdown
     attributes:
       value: |
-        Thanks for taking the time to fill out this bug report! Please provide as much information as possible and make sure you have checked the [documentation](https://stack.jimmycai.com/).
+        Thanks for taking the time to fill out this bug report! Please provide as much information as possible and make sure you have checked the [documentation](https://stack.jimmycai.com/guide/).
   - type: textarea
     id: what-happened
     attributes:

exampleSite/hugo.yaml

@@ -203,7 +203,7 @@ params:
             enabled: true
 
 ### Custom menu
-### See https://docs.stack.jimmycai.com/configuration/custom-menu.html
+### See https://stack.jimmycai.com/config/menu
 ### To remove about, archive and search page menu item, remove `menu` field from their FrontMatter
 menu:
     main: []

layouts/partials/sidebar/left.html

@@ -65,7 +65,7 @@
             <a href='{{ .URL }}' {{ if eq .Params.newTab true }}target="_blank"{{ end }}>
                 {{ $icon := default .Pre .Params.Icon }}
                 {{ if .Pre }}
-                    {{ warnf "Menu item [%s] is using [pre] field to set icon, please use [params.icon] instead.\nMore information: https://docs.stack.jimmycai.com/configuration/custom-menu.html" .URL }}
+                    {{ warnf "Menu item [%s] is using [pre] field to set icon, please use [params.icon] instead.\nMore information: https://stack.jimmycai.com/config/menu" .URL }}
                 {{ end }}
                 {{ with $icon }}
                     {{ partial "helper/icon" . }}