Replace angle brackets in example code by proper unicode symbol

[ThomDietrich]

Example code is full of placeholders, e.g. http://docs.openhab.org/configuration/sitemaps.html#element-type-switch

Switch item=<itemname> [label="<labelname>"] [icon="<iconname>"]

The use of <> is confusing in certain situations. I just realized that another symbol (unicode) is commonly used for these cases. http://www.fileformat.info/info/unicode/char/3008/index.htm

Switch item=〈itemname〉 [label="〈labelname〉"] [icon="〈iconname〉"]

If the introduced space is not desired, we can also go with http://www.fileformat.info/info/unicode/char/2329/index.htm

Switch item=〈itemname〉 [label="〈labelname〉"] [icon="〈iconname〉"]