tpl: Add hasSuffix alias

strings.HasPrefix already has an alias of hasPrefix
but strings.HasSuffix has no such alias.
This PR adds a hasSuffix alias to the tpl function with corresponding
function documentation.
It also adds a Minor update to the hasPrefix function documentation
re: keywords and relatedfuncs.

 Completes gohugoio/hugo#10474

content/en/functions/hasPrefix.md

@@ -9,11 +9,11 @@ categories: [functions]
 menu:
   docs:
     parent: "functions"
-keywords: []
+keywords: [strings]
 signature: ["hasPrefix STRING PREFIX"]
 workson: []
 hugoversion:
-relatedfuncs: []
+relatedfuncs: [hasSuffix]
 deprecated: false
 aliases: []
 ---

content/en/functions/hasSuffix.md

@@ -0,0 +1,21 @@
+---
+title: hassuffix
+linktitle: hasSuffix
+description: Tests whether a string ends with suffix.
+date: 2023-03-01
+publishdate: 2023-03-01
+lastmod: 2023-03-01
+categories: [functions]
+menu:
+docs:
+parent: "functions"
+keywords: [strings]
+signature: ["hasSuffix STRING SUFFIX"]
+workson: []
+hugoversion:
+relatedfuncs: [hasPrefix]
+deprecated: false
+aliases: []
+---
+
+* `{{ hasSuffix "Hugo" "go" }}` → true