Remove support for modifying request parameters

Request parameters are a server-side constructor, specific to the
servlet specification. Rather than modifying request parameters the
query string of the URI or the form URL encoded content of the body
should be modified instead.

Closes gh-846

Author: wilkinsona

docs/src/docs/asciidoc/customizing-requests-and-responses.adoc

@@ -123,13 +123,6 @@ Any occurrences that match a regular expression are replaced.
 
 
 
-[[customizing-requests-and-responses-preprocessors-modify-request-parameters]]
-==== Modifying Request Parameters
-
-You can use `modifyParameters` on `Preprocessors` to add, set, and remove request parameters.
-
-
-
 [[customizing-requests-and-responses-preprocessors-modify-uris]]
 ==== Modifying URIs
 

spring-restdocs-core/src/main/java/org/springframework/restdocs/operation/preprocess/ParametersModifyingOperationPreprocessor.java

@@ -137,16 +137,6 @@ public static OperationPreprocessor replacePattern(Pattern pattern, String repla
 		return new ContentModifyingOperationPreprocessor(new PatternReplacingContentModifier(pattern, replacement));
 	}
 
-	/**
-	 * Returns a {@code ParametersModifyingOperationPreprocessor} that can then be
-	 * configured to modify the parameters of the request.
-	 * @return the preprocessor
-	 * @since 1.1.0
-	 */
-	public static ParametersModifyingOperationPreprocessor modifyParameters() {
-		return new ParametersModifyingOperationPreprocessor();
-	}
-
 	/**
 	 * Returns a {@code HeadersModifyingOperationPreprocessor} that can then be configured
 	 * to modify the headers of the request or response.