Specify config file names. Relates to https://github.com/jreleaser/jreleaser/issues/136

docs/modules/configuration/pages/environment.adoc

@@ -137,8 +137,9 @@ Formats currently supported for the properties file are:
 ====
 PROPERTIES::
 +
-[source,yaml]
+[source,properties]
 [subs="+macros"]
+.config.properties
 ----
 JRELEASER_GITHUB_TOKEN = b9df0920aefcbfa69f57c4f02bae4396
 ----
@@ -146,6 +147,7 @@ YAML::
 +
 [source,yaml]
 [subs="+macros"]
+.config.yml
 ----
 JRELEASER_GITHUB_TOKEN: b9df0920aefcbfa69f57c4f02bae4396
 ----
@@ -153,6 +155,7 @@ TOML::
 +
 [source,toml]
 [subs="+macros"]
+.config.toml
 ----
 JRELEASER_GITHUB_TOKEN = "b9df0920aefcbfa69f57c4f02bae4396"
 ----
@@ -160,6 +163,7 @@ JSON::
 +
 [source,json]
 [subs="+macros"]
+.config.json
 ----
 {
   "JRELEASER_GITHUB_TOKEN": "b9df0920aefcbfa69f57c4f02bae4396"
@@ -167,6 +171,8 @@ JSON::
 ----
 ====
 
+NOTE: The config file must use the appropriate file extension that matches the format in use.
+
 == Maven
 
 JReleaser will honor Maven project properties. These properties can be defined in several ways: