GCC: Avoid symbol clash in RenderBuffer

GCC fails to resolve getter for RenderBuffer::Block() because
its return type has the same name with the getter method.
Rename getter method with the prefix "Get" as guided in the
https://chromium.googlesource.com/chromium/src/+/main/styleguide/c++/blink-c++.md#Precede-setters-with-the-word-Set_use-bare-words-for-getters
"If a getter’s name collides with a type name, prefix it with “Get”."

Bug: chromium:819294, webrtc:14089
Change-Id: Ieaa3af27415eb8c39806aa8480897b47fd07baa8
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/263420
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36982}

modules/audio_processing/aec3/render_buffer.h

@@ -40,7 +40,7 @@ class RenderBuffer {
   ~RenderBuffer();
 
   // Get a block.
-  const Block& Block(int buffer_offset_blocks) const {
+  const Block& GetBlock(int buffer_offset_blocks) const {
     int position =
         block_buffer_->OffsetIndex(block_buffer_->read, buffer_offset_blocks);
     return block_buffer_->buffer[position];