Address review comments

[xluciano]

Part of https://xmosjira.atlassian.net/browse/AP-236

[BrennanGit]

Sorry I was in a meeting for a while. For reference, my exclude patterns now looks like this:

# The following patterns are to be excluded from the documentation build
tools
projects
test
xmos_cmake_toolchain
modules/**/thirdparty
modules/FreeRTOS
modules/sw_services
build
build_*
**CHANGELOG*
**LICENSE*
**README* 

The only other thing that leaps out is this error: index.rst:19: WARNING: Failed to create a cross reference. A title or caption not found: 'fwk_rtos_copyright'

I think this is because the section it refers to is included twice, once by each document. Might I suggest we just remove the licensing section from the top-level index.rst? I'd think it's visible enough as it is.

[xluciano]

Sorry I was in a meeting for a while. For reference, my exclude patterns now looks like this:

# The following patterns are to be excluded from the documentation build
tools
projects
test
xmos_cmake_toolchain
modules/**/thirdparty
modules/FreeRTOS
modules/sw_services
build
build_*
**CHANGELOG*
**LICENSE*
**README* 

The only other thing that leaps out is this error: index.rst:19: WARNING: Failed to create a cross reference. A title or caption not found: 'fwk_rtos_copyright'

I think this is because the section it refers to is included twice, once by each document. Might I suggest we just remove the licensing section from the top-level index.rst? I'd think it's visible enough as it is.

I removed that reference and rephrased the text. See 4e07363.

[BrennanGit]

The last issue is this: programming_guide/platform.rst:3: WARNING: Duplicate explicit target name: "xtc tools"

Buit this appears to be fixed on develop already