Run IntelliJ's analysis on OkHttp.

This made a few hundred suggestions, many of which are thoughtful but
I'm deliberately ignoring anyway.

The following fixes are good ideas.

okhttp-logging-interceptor/src/main/java/okhttp3/logging/HttpLoggingInterceptor.java

@@ -274,7 +274,7 @@ public final class HttpLoggingInterceptor implements Interceptor {
    * Returns true if the body in question probably contains human readable text. Uses a small sample
    * of code points to detect unicode control characters commonly used in binary file signatures.
    */
-  static boolean isPlaintext(Buffer buffer) throws EOFException {
+  static boolean isPlaintext(Buffer buffer) {
     try {
       Buffer prefix = new Buffer();
       long byteCount = buffer.size() < 64 ? buffer.size() : 64;