Add doc search

doc/decimal-playbook.yml

@@ -12,3 +12,7 @@ ui:
   bundle:
     url: https://github.com/boostorg/website-v2-docs/releases/download/ui-master/ui-bundle.zip
   output_dir: decimal/_
+antora:
+  extensions:
+    - '@antora/lunr-extension'
+

doc/modules/ROOT/pages/examples.adoc

@@ -276,7 +276,7 @@ int main()
 [#examples_fmt_format]
 === `<fmt/format.hpp>`
 
-We also provide support for `{fmt}` so you can easily just swap the namespaces and headers on the above example:
+We also provide support for pass:[{fmt}] so you can easily just swap the namespaces and headers on the above example:
 
 [source, c++]
 ----

doc/modules/ROOT/pages/format.adoc

@@ -71,7 +71,7 @@ int main()
 [#fmt_format]
 == `<fmt/format.h>`
 
-Support for `{fmt}` is available as long as `<fmt/format.h>` is present.
+Support for pass:[{fmt}] is available as long as `<fmt/format.h>` is present.
 All the above information on modifiers is the same for fmtlib, just in a different namespace (i.e. `fmt::` instead of `std::`).
 
 [source, c++]