build: move syntax files to contrib/syntax/files

Having all of syntax files in the same directory makes it easier to
reference all of them at once on a makefile (such as with
`contrib/syntax/files/*.in`).

Also, this makes the path to the gtksourceview language-spec shorter.
Current path/new path:

* contrib/gtksourceview-5/language-specs/firejail-profile.lang
* contrib/syntax/files/firejail-profile.lang

Currently, adding a rule to the root Makefile to generate the
language-spec in the same directory as an input file would take at least
95 characters (with only a single dependency):

    contrib/gtksourceview-5/language-specs/%.lang: contrib/gtksourceview-5/language-specs/%.lang.in

With this commit, the above shortened to 59 characters:

    contrib/syntax/files/%.lang: contrib/syntax/files/%.lang.in

Which should make it more readable.

Relates to #2679 #5502.

.github/workflows/build-extra.yml

@@ -5,7 +5,7 @@ on:
     branches: [ master ]
     paths-ignore:
       - '.github/ISSUE_TEMPLATE/*'
-      - 'contrib/gtksourceview-5/**'
+      - 'contrib/syntax/**'
       - 'contrib/vim/**'
       - 'etc/**'
       - 'src/man/*.txt'
@@ -27,7 +27,7 @@ on:
     branches: [ master ]
     paths-ignore:
       - '.github/ISSUE_TEMPLATE/*'
-      - 'contrib/gtksourceview-5/**'
+      - 'contrib/syntax/**'
       - 'contrib/vim/**'
       - 'etc/**'
       - 'src/man/*.txt'

.github/workflows/codeql-analysis.yml

@@ -10,7 +10,7 @@ on:
     branches: [ master ]
     paths-ignore:
       - '.github/ISSUE_TEMPLATE/*'
-      - 'contrib/gtksourceview-5/**'
+      - 'contrib/syntax/**'
       - 'contrib/vim/**'
       - 'etc/**'
       - 'src/man/*.txt'
@@ -32,7 +32,7 @@ on:
     branches: [ master ]
     paths-ignore:
       - '.github/ISSUE_TEMPLATE/*'
-      - 'contrib/gtksourceview-5/**'
+      - 'contrib/syntax/**'
       - 'contrib/vim/**'
       - 'etc/**'
       - 'src/man/*.txt'

Makefile

@@ -124,10 +124,10 @@ ifeq ($(HAVE_CONTRIB_INSTALL),yes)
 	install -m 0755 -d $(DESTDIR)$(datarootdir)/vim/vimfiles/ftdetect
 	install -m 0755 -d $(DESTDIR)$(datarootdir)/vim/vimfiles/syntax
 	install -m 0644 contrib/vim/ftdetect/firejail.vim $(DESTDIR)$(datarootdir)/vim/vimfiles/ftdetect
-	install -m 0644 contrib/vim/syntax/firejail.vim $(DESTDIR)$(datarootdir)/vim/vimfiles/syntax
-	# gtksourceview-5 language-specs
+	install -m 0644 contrib/syntax/files/firejail.vim $(DESTDIR)$(datarootdir)/vim/vimfiles/syntax
+	# gtksourceview language-specs
 	install -m 0755 -d $(DESTDIR)$(datarootdir)/gtksourceview-5/language-specs
-	install -m 0644 contrib/gtksourceview-5/language-specs/firejail-profile.lang $(DESTDIR)$(datarootdir)/gtksourceview-5/language-specs
+	install -m 0644 contrib/syntax/files/firejail-profile.lang $(DESTDIR)$(datarootdir)/gtksourceview-5/language-specs
 endif
 	# documents
 	install -m 0755 -d $(DESTDIR)$(docdir)