docs/phonemes.md: move the remaining articulation diacritics to a new positioning diacritics section.

docs/phonemes.md

   - [Other Symbols](#other-symbols)
   - [Gemination](#gemination)
   - [Vowels](#vowels)
+  - [Positioning Diacritics](#positioning-diacritics)
 - [Features](#features)
   - [Air Flow](#air-flow)
   - [Initiator](#initiator)
 distinction is not needed to classify these vowels, so is not included in the
 above table.
 
+#### Positioning Diacritics
+
+The following IPA diacritics are only used by eSpeak NG to fill out positions
+in the IPA consonant and vowel charts. As such those phonemes are transcribed
+according to the features at that position, not using the features at the
+location of the base phoneme with a feature for each of the positioning
+diacritics.
+
+| Symbol | Name            |
+|--------|-----------------|
+| ◌̟      | advanced        |
+| ◌̠      | retracted       |
+| ◌̈      | centralized     |
+| ◌̽      | mid-centralized |
+| ◌̝      | raised          |
+| ◌̞      | lowered         |
+
 ## Features
 
 ### Air Flow
 the Jawoyn, Ojibwe, and Zurich German languages<sup>\[<a href="#ref8">8</a>\]</sup>),
 the [length](#length) suprasegmentals are used instead.
 
-#### Articulation
-
-The following IPA diacritics are only used by eSpeak NG to fill out positions
-in the IPA consonant and vowel charts. As such those phonemes are transcribed
-according to the features at that position, not using the features at the
-location of the base phoneme with a feature for each of the positioning
-diacritics.
-
-| IPA | Name            |
-|-----|-----------------|
-| ◌̟   | advanced        |
-| ◌̠   | retracted       |
-| ◌̈   | centralized     |
-| ◌̽   | mid-centralized |
-| ◌̝   | raised          |
-| ◌̞   | lowered         |
-
 #### Co-articulation
 
 | Feature | Kirshenbaum | IPA | Name            |