Add support for font-specific formats (#3142)

* markdown and font-specific updates languages.yml

- Markdown: ← extensions: .md.txt
- Text: ← extensions: .text
- Text: ← filenames: FONTLOG http://scripts.sil.org/cms/scripts/page.php?item_id=OFL-FAQ_web#43cecb44
- OpenType: ← extensions: .fea https://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html
- Spline Font: ← extensions: .sfd http://fontforge.github.io/en-US/documentation/developers/sfdformat/

* Update languages.yml

`type: data` for SFD

* Update languages.yml

OpenType feature ← type: markup

* Update languages.yml

alphabetic order

* Update languages.yml

incorporated suggestions:

- “OpenType Font Feature” → “Opentype feature” (no “file” at the end, because that’s left out almost everywhere else, too)
- `tm_scope` according to https://github.com/Alhadis/language-fontforge

* remove non-font related additions

- `.md.txt` Markdown
- `.text` Plain Text

* Update languages.yml

remove comment

* changed names as requested

* Merge remote-tracking branch 'github/master' into patch-2

# Conflicts:
#	lib/linguist/languages.yml

* quote marks

* Revert "Merge remote-tracking branch 'github/master' into patch-2"

This reverts commit 18e4256b828c4186fec806319cbf8b76f0d2c79b.

* Update language IDs

* Add missing submodule to grammars list

lib/linguist/languages.yml

@@ -1141,9 +1141,9 @@ Emacs Lisp:
   - ".gnus"
   - ".spacemacs"
   - ".viper"
-  - "Project.ede"
-  - "_emacs"
-  - "abbrev_defs"
+  - Project.ede
+  - _emacs
+  - abbrev_defs
   extensions:
   - ".el"
   - ".emacs"
@@ -2956,6 +2956,15 @@ OpenSCAD:
   - ".scad"
   tm_scope: none
   ace_mode: scad
+  language_id: 431
+OpenType Feature File:
+  type: data
+  aliases:
+  - AFDKO
+  extensions:
+  - ".fea"
+  tm_scope: source.opentype
+  ace_mode: text
   language_id: 266
 Org:
   type: prose
@@ -3175,7 +3184,7 @@ Perl6:
 Pic:
   type: markup
   group: Groff
-  tm_scope: "source.pic"
+  tm_scope: source.pic
   extensions:
   - ".pic"
   - ".chem"
@@ -4030,6 +4039,13 @@ SourcePawn:
   - ".sma"
   tm_scope: source.sp
   ace_mode: text
+  language_id: 432
+Spline Font Database:
+  type: data
+  extensions:
+  - ".sfd"
+  tm_scope: text.sfd
+  ace_mode: yaml
   language_id: 354
 Squirrel:
   type: programming
@@ -4261,6 +4277,7 @@ Text:
   - ".no"
   filenames:
   - COPYING
+  - FONTLOG
   - INSTALL
   - LICENSE
   - NEWS