Update the --add-exports instructions.

I don't really understand _why_ this works. I'm able to (easily) reproduce the
problem by not including the `=` in my `idea64.options` file. But then if I
copy/paste the command line out of `ps`, it works fine.

And since it's easy enough to change this, I'm inclined to just do that?

Fixes #908.

PiperOrigin-RevId: 514440074

Author: plumpy

Diff for: README.md

@@ -54,12 +54,12 @@ without extra configuration. To use the plugin, go to `Help→Edit Custom VM
 Options...` and paste in these lines:
 
 ```
---add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
---add-exports jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
---add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
---add-exports jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED
---add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
---add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
 ```
 
 Once you've done that, restart the IDE.
@@ -105,12 +105,12 @@ following JVM flags are required when running on JDK 16 and newer, due to
 [JEP 396: Strongly Encapsulate JDK Internals by Default](https://openjdk.java.net/jeps/396):
 
 ```
---add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
---add-exports jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
---add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
---add-exports jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED
---add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
---add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
 ```
 
 #### Maven