Add an opt-in option to lowercase filter values

Filter values that only differ in case, like `Mint` and `mint`, came
through as separate values. The new `--lowercase-filters` option
(`lowercase_filters`, `PAGEFIND_LOWERCASE_FILTERS`, and
`lowercaseFilters` / `lowercase_filters` in the Node and Python
wrappers) lowercases filter values when indexing and merges values on
a page that become equal. Filter names are left as they are. Off by
default.

Fixes #737

docs/content/docs/config-options.md

@@ -121,6 +121,15 @@ This defaults to false, so playground files are not written to your live site. P
 |----------------------|--------------------|--------------------|
 | `--write-playground` | `PAGEFIND_WRITE_PLAYGROUND` | `write_playground` |
 
+### Lowercase filters
+Lowercases all filter values when indexing, so that values differing only in case are merged. With this option, `<span data-pagefind-filter="garnish">Mint</span>` and `<span data-pagefind-filter="garnish">mint</span>` both come through as the `mint` value of the `garnish` filter. Filter names are left as they are.
+
+Filter values passed to Pagefind search should then be lowercase too, and any UI that displays them will show the lowercased values.
+
+| CLI Flag              | ENV Variable                 | Config Key          |
+|-----------------------|------------------------------|---------------------|
+| `--lowercase-filters` | `PAGEFIND_LOWERCASE_FILTERS` | `lowercase_filters` |
+
 ### Verbose
 Prints extra logging while indexing the site. Only affects the CLI, does not impact web-facing search.
 

docs/content/docs/node-api.md

@@ -64,6 +64,7 @@ const { index } = await pagefind.createIndex({
     excludeSelectors: [".my-code-blocks"],
     forceLanguage: "en",
     includeCharacters: "._",
+    lowercaseFilters: false,
     keepIndexUrl: false,
     writePlayground: false,
     verbose: false,

docs/content/docs/py-api.md

@@ -131,6 +131,7 @@ config = IndexConfig(
     exclude_selectors=["nav"],
     force_language="en",
     include_characters="._",
+    lowercase_filters=False,
     verbose=True,
     logfile="index.log",
     keep_index_url=True,