assignments: fixed useless quotes surronding code samples

* source/compiler_stages/tc_2/code_to_write.rst,
* source/compiler_stages/tc_2/given_code.rst,
* source/compiler_stages/tc_2/pretty_printing_samples.rst,
* source/compiler_stages/tc_3/faq.rst,
* source/compiler_stages/tc_3/given_code.rst,
* source/compiler_stages/tc_4/given_code.rst,
* source/compiler_stages/tc_5/code_to_write.rst,
* source/compiler_stages/tc_5/given_code.rst,
* source/compiler_stages/tc_5/goals.rst,
* source/compiler_stages/tc_5/improvements.rst,
* source/compiler_stages/tc_5/optimizing_cascading_if.rst,
* source/compiler_stages/tc_5/primitive_samples.rst,
* source/compiler_stages/tc_e/code_to_write.rst,
* source/source_code/given_code.rst,
* source/source_code/project_layout/build_aux.rst,
* source/source_code/project_layout/src_ast.rst,
* source/source_code/project_layout/src_bind.rst,
* source/source_code/project_layout/src_escapes.rst,
* source/source_code/project_layout/src_overload.rst,
* source/source_code/project_layout/src_parse.rst,
* source/source_code/project_layout/src_translate.rst,
* source/source_code/project_layout/src_type.rst,
* source/source_code/project_layout/the_top_level.rst: here.
1 job for master in 30 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #31371
trigger-tc

00:00:30