Improve handling of requests with both parameters and content

Previously, if a MockMvc request was made with parameters and body
content, the parameters were omitted from the resulting curl, HTTPie
and HTTP request snippets.

This commit updates the affected snippets to ensure that the
parameters are included. The user-provided content is interpreted
as indicating that the parameters should be sent in the query string
rather than as form-encoded content.

Closes gh-239

spring-restdocs-mockmvc/src/test/java/org/springframework/restdocs/mockmvc/MockMvcRestDocumentationIntegrationTests.java

@@ -175,6 +175,22 @@ public class MockMvcRestDocumentationIntegrationTests {
 								+ "-H 'Accept: application/json' -d 'a=alpha'"))));
 	}
 
+	@Test
+	public void curlSnippetWithContentAndParametersOnPost() throws Exception {
+		MockMvc mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
+				.apply(documentationConfiguration(this.restDocumentation)).build();
+		mockMvc.perform(post("/").param("a", "alpha").accept(MediaType.APPLICATION_JSON)
+				.content("some content")).andExpect(status().isOk())
+				.andDo(document("curl-snippet-with-content-and-parameters"));
+		assertThat(
+				new File(
+						"build/generated-snippets/curl-snippet-with-content-and-parameters/curl-request.adoc"),
+				is(snippet(asciidoctor())
+						.withContents(codeBlock(asciidoctor(), "bash").content("$ curl "
+								+ "'http://localhost:8080/?a=alpha' -i -X POST "
+								+ "-H 'Accept: application/json' -d 'some content'"))));
+	}
+
 	@Test
 	public void httpieSnippetWithContent() throws Exception {
 		MockMvc mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
@@ -207,6 +223,22 @@ public class MockMvcRestDocumentationIntegrationTests {
 								+ "'Accept:application/json' 'a=alpha'"))));
 	}
 
+	@Test
+	public void httpieSnippetWithContentAndParametersOnPost() throws Exception {
+		MockMvc mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
+				.apply(documentationConfiguration(this.restDocumentation)).build();
+		mockMvc.perform(post("/").param("a", "alpha").content("some content")
+				.accept(MediaType.APPLICATION_JSON)).andExpect(status().isOk())
+				.andDo(document("httpie-snippet-post-with-content-and-parameters"));
+		assertThat(
+				new File(
+						"build/generated-snippets/httpie-snippet-post-with-content-and-parameters/httpie-request.adoc"),
+				is(snippet(asciidoctor()).withContents(codeBlock(asciidoctor(), "bash")
+						.content("$ echo " + "'some content' | http POST "
+								+ "'http://localhost:8080/?a=alpha' "
+								+ "'Accept:application/json'"))));
+	}
+
 	@Test
 	public void linksSnippet() throws Exception {
 		MockMvc mockMvc = MockMvcBuilders.webAppContextSetup(this.context)