docs: add strcontains function doc

website/content/docs/templates/hcl_templates/functions/string/strcontains.mdx

@@ -0,0 +1,25 @@
+---
+page_title: strcontains - Functions - Configuration Language
+description: |-
+  The strcontains function checks whether a given string can be found within another string.
+---
+
+# `strcontains` Function
+
+`strcontains` function checks whether a substring is within another string.
+
+```hcl
+strcontains(string, substr)
+```
+
+## Examples
+
+```
+> strcontains("hello world", "wor")
+true
+```
+
+```
+> strcontains("hello world", "wod")
+false
+```

website/data/docs-nav-data.json

@@ -285,6 +285,10 @@
                     "title": "split",
                     "path": "templates/hcl_templates/functions/string/split"
                   },
+                  {
+                    "title": "strcontains",
+                    "path": "templates/hcl_templates/functions/string/strcontains"
+                  },
                   {
                     "title": "strrev",
                     "path": "templates/hcl_templates/functions/string/strrev"