Document PreserveTaxonomyNames

Fixes gohugoio#1648

docs/content/overview/configuration.md

@@ -115,7 +115,9 @@ Following is a list of Hugo-defined variables that you can configure and their c
     paginatePath:               "page"
     permalinks:
     # Pluralize titles in lists using inflect
-    pluralizeListTitles:         true
+    pluralizeListTitles:        true
+    # Preserve special characters in taxonomy names ("Gérard Depardieu" vs "Gerard Depardieu")
+    preserveTaxonomyNames:      false
     publishdir:                 "public"
     # color-codes for highlighting derived from this style
     pygmentsStyle:              "monokai"

docs/content/taxonomies/usage.md

@@ -53,7 +53,19 @@ Assigning content to an taxonomy is done in the front matter.
 Simply create a variable with the *plural* name of the taxonomy
 and assign all terms you want to apply to this content.
 
-**taxonomy values are case insensitive**
+## Preserving taxonomy values
+
+By default, taxonomy names are hyphenated, lower-cased and normalized, and then
+fixed and titleized on the archive page.
+
+However, if you want to have a taxonomy value with special characters
+such as `Gérard Depardieu` instead of `Gerard Depardieu`,
+you need to set the `preserveTaxonomyNames` [site configuration](/overview/configuration/) variable to `true`.
+Hugo will then preserve special characters in taxonomy values
+but will still titleize the values for titles and normalize them in URLs.
+
+Note that if you use `preserveTaxonomyNames` and intend to manually construct URLs to the archive pages,
+you will need to pass the taxonomy values through the `urlize` template function.
 
 ### Front Matter Example (in TOML)