Remove references of shims folder in docs [skip ci] (#5009)

* removing mention of shims folder in docs

Signed-off-by: Raza Jafri <rjafri@nvidia.com>

* empty commit to stop requiring CI

Signed-off-by: Raza Jafri <rjafri@nvidia.com>

* Update CONTRIBUTING.md

Co-authored-by: Jason Lowe <jlowe@nvidia.com>

Co-authored-by: Raza Jafri <rjafri@nvidia.com>
Co-authored-by: Jason Lowe <jlowe@nvidia.com>

CONTRIBUTING.md

@@ -160,11 +160,9 @@ Spark version, open [Maven tool window](https://www.jetbrains.com/help/idea/2021
 select one of the `release3xx` profiles (e.g, `release320`) for Apache Spark 3.2.0, and click "Reload"
 if not triggered automatically.
 
-There is a known issue with the shims/spark3xx submodules. After being enabled once, a module such as shims/spark312
-may remain active in IDEA even though you explicitly disable the Maven profile `release312` in the Maven tool window.
-With an extra IDEA shim module loaded the IDEA internal build "Build->Build Project" is likely to fail
-(whereas it has no adverse effect on Maven build). As a workaround, locate the pom.xml under the extraneous IDEA module,
-right-click on it and select "Maven->Ignore Projects".
+There is a known issue where, even after selecting a different Maven profile in the Maven submenu, the source folders from 
+a previously selected profile may remain active. To get around this you have to manually reload the Maven project from 
+the Maven side menu.
 
 If you see Scala symbols unresolved (highlighted red) in IDEA please try the following steps to resolve it:
 - Make sure there are no relevant poms in "File->Settings->Build Tools->Maven->Ignored Files"

docs/dev/shims.md

@@ -89,10 +89,9 @@ by having the documented facade classes with a shim specifier in their package n
 The second issue that every parent class/trait in the inheritance graph is loaded using the classloader outside 
 Plugin's control. Therefore, all this bytecode must reside in the conventional jar location, and it must 
 be bitwise-identical across *all* shims. The only way to keep the source code for shared functionality unduplicated,
-(i.e., in `sql-plugin/src/main/scala` as opposed to be duplicated either in `shims/spark3xx` submodules or over
-`sql-plugin/src/main/3*/scala` source code roots) is to delay inheriting `ShuffleManager` until as late as possible, 
-as close as possible to the facade class where we have to split the source code anyways. Use traits as much 
-as possible for flexibility. 
+(i.e., in `sql-plugin/src/main/scala` as opposed to be duplicated in `sql-plugin/src/main/3*/scala` source code roots) 
+is to delay inheriting `ShuffleManager` until as late as possible, as close as possible to the facade class where we 
+have to split the source code anyway. Use traits as much as possible for flexibility. 
 
 ### Late Initialization of Public Classes' Ancestors