Add bibclen fixer support

Closes #1910

doc/ale-bib.txt

@@ -0,0 +1,19 @@
+===============================================================================
+ALE BibTeX Integration                                        *ale-bib-options*
+
+
+===============================================================================
+bibclean                                                     *ale-bib-bibclean*
+
+g:ale_bib_bibclean_executable                   *g:ale_bib_bibclean_executable*
+
+  Type: |String|
+  Default: `'bibclean'`
+
+g:ale_bib_bibclean_options                         *g:ale_bib_bibclean_options*
+
+  Type: |String|
+  Default: `'-align-equals'`
+
+===============================================================================
+vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl:

doc/ale.txt

@@ -31,6 +31,8 @@ CONTENTS                                                         *ale-contents*
       gcc.................................|ale-asm-gcc|
     awk...................................|ale-awk-options|
       gawk................................|ale-awk-gawk|
+    bib...................................|ale-bib-options|
+      bibclean............................|ale-bib-bibclean|
     c.....................................|ale-c-options|
       clang...............................|ale-c-clang|
       clangd..............................|ale-c-clangd|
@@ -403,6 +405,7 @@ Notes:
 * AsciiDoc: `alex`!!, `proselint`, `redpen`, `write-good`, `vale`
 * Awk: `gawk`
 * Bash: `language-server`, `shell` (-n flag), `shellcheck`, `shfmt`
+* BibTeX: `bibclean`
 * Bourne Shell: `shell` (-n flag), `shellcheck`, `shfmt`
 * C: `cppcheck`, `cpplint`!!, `clang`, `clangd`, `clangtidy`!!, `clang-format`, `cquery`, `flawfinder`, `gcc`, `uncrustify`, `ccls`
 * C++ (filetype cpp): `clang`, `clangd`, `clangcheck`!!, `clangtidy`!!, `clang-format`, `clazy`!!, `cppcheck`, `cpplint`!!, `cquery`, `flawfinder`, `gcc`, `uncrustify`, `ccls`