Fix REST API section titles in config page

"REST" should be capitalised.

Change-Id: I9f6e3208459cc9e41e6b98f62f41f3051f4f399b
Refer to "plugins", not "plug-ins"

They are referred to as "plugins" in the Jenkins admin page,
so make it consistent with that.

Change-Id: Ie56f6a732c1377c9d7033c75463efd21f781353e
Abbreviate "Number" as "No." instead of "Nr"

"No." is the correct abbreviation in English.

Change-Id: I89376898c3d623bdd4d5d560ae7234a781895ed8
Don't abbreviate "Miscellaneous"

Change-Id: I20d541a3a5a6d14efe318a68d60d172b8a1272b0
Use consistent capitalisation for sections on settings pages

Change-Id: Ice4ecec43c165866413ccc343e8f724f8943368d
Improve help text for unreviewed patch sets feature

Change-Id: Iee0179651a63adc749b52725bdaf574cb3a55bec
Merge pull request #142 from dpursehouse/ui-tweaks

Various corrections in the UI texts