Resolve HLint warnings

All warnings are either fixed or, if more appropriate, HLint is
configured to ignore them. HLint suggestions remain.

  * Ignore "Use camelCase" warnings in Lua and legacy code
  * Fix or ignore remaining HLint warnings
  * Remove redundant brackets
  * Remove redundant `return`s
  * Remove redundant as-pattern
  * Fuse mapM_/map
  * Use `.` to shorten code
  * Remove redundant `fmap`
  * Remove unused LANGUAGE pragmas
  * Hoist `not` in Text.Pandoc.App
  * Use fewer imports for `Text.DocTemplates`
  * Remove redundant `do`s
  * Remove redundant `$`s
  * Jira reader: remove unnecessary parentheses

1 files changed, 22 insertions, 9 deletions

diff --git a/.hlint.yaml b/.hlint.yaml
index def675e77..cc4ee4fea 100644
--- a/.hlint.yaml
+++ b/.hlint.yaml
@@ -55,18 +55,31 @@
 # - ignore: {name: "Use list comprehension"}
 # - ignore: {name: "Redundant if"}
 - ignore: {name: "Avoid lambda"}
-- ignore: {name: "Use String"}
-- ignore: {name: "Use isDigit"}
 - ignore: {name: "Eta reduce"}
-- ignore: {name: "Use fmap"}  # specific for GHC 7.8 compat
-- ignore: {name: "Parse error"}  # we trust the compiler over HLint
-- ignore: {name: "Use =="}  # Creates infinite loops in `EQ` using expressions
 - ignore: {name: "Evaluate"}
+- ignore: {name: "Monad law, left identity", module: "Text.Pandoc.App.OutputSettings"}
+- ignore: {name: "Parse error"}  # we trust the compiler over HLint
+- ignore: {name: "Reduce duplication", module: "Text.Pandoc.Readers.Markdown"}
 - ignore: {name: "Use &&&"}
-# - ignore: {name: "Redundant compare"}
+- ignore: {name: "Use =="}  # Creates infinite loops in `EQ` using expressions
+- ignore: {name: "Use String"}
+- ignore: {name: "Use fmap"}  # specific for GHC 7.8 compat
+- ignore: {name: "Use forM_", module: "Text.Pandoc.Readers.DocBook"}
+- ignore: {name: "Use isDigit"}
+- ignore: {name: "Use tuple-section", module: "Text.Pandoc.Readers.EPUB"}
+- ignore: {name: "Use uncurry", module: "Text.Pandoc.Readers.Docx.Combine"}
+- ignore:
+    name: "Use <$>"
+    within:
+      - Text.Pandoc.Readers.LaTeX
+      - Text.Pandoc.Readers.Markdown
+- ignore:
+    name: "Use camelCase"
+    within:
+      - Text.Pandoc.Extensions
+      - Text.Pandoc.Lua.Marshalling.Version
+      - Text.Pandoc.Readers.Odt.ContentReader
+      - Text.Pandoc.Readers.Odt.Namespaces
 
 # Define some custom infix operators
 # - fixity: infixr 3 ~^#^~
-
-
-